Privacy Policy

Data Protection Statement

I (Joachim K. Rennstich (“JKR”)) am pleased to see you visiting my website. Thank you for your interest. This data protection statement describes the privacy policy for this personal academic website and and governs the privacy of those who use it. The purpose of this policy is to explain to you how I control, process, handle and protect your personal information while browsing or using this website, including your rights under current laws and regulations. If you do not agree to the following policy you may wish to cease viewing/using this website.

Policy key definitions

Your individual rights

Under the GDPR your rights are as follows:

  • the right to be informed,
  • the right of access,
  • the right to rectification,
  • the right to erasure,
  • the right to restrict processing,
  • the right to data portability,
  • the right to object, and
  • the right not to be subject to automated decision-making including profiling.

You also have the right to complain to the BfDI if you feel there is a problem with the way I am handling your data.

I handle subject access requests in accordance with the GDPR and German law.

Responsible for content (Angaben gem. § 5 TMG, § 55 Abs. 2 RStV and § 6 MDStV)

Joachim Rennstich
Hugo-Preuß-Str. 31
34131 Kassel

Phone: +49 561 3087526
Email: joachim[at]

The copyright for all texts as well as graphics on this and all others pages remains with the author(s). The download as well as the print-out of texts, images and graphical elements is only permitted for private and non-commercal purposes unless explicitly stated otherwise.

Object of data protection

The object of data protection is personal data. Personal data means any information relating to an identified or identifiable natural person (a so-called data subject). This includes, for example, details such as the name, postal address, email address and phone number, though other details are also necessarily created while using our website, such as the beginning, end and extent of use.

I aim to minimize the collection of any such personal data through the use of this website. In most instances, no personal data are collected as a result of your use of this site. If any personal data are collected, you have volunteered this information or consented to the collection of such data.

Below you will find an overview of the type, scope, purposes and legal basis of data processing on my website.

Provision of my website

When you access my website on your device, I process the following data:

  • Date and time of access
  • Duration of visit
  • Your operating system
  • Volume of data sent
  • Type of access
  • IP address

I process these data on the basis of GDPR Article 6 (1) point f, as they are required for me to provide the service, to ensure technical operation and to investigate and remove malfunctions. It is in my interest to ensure the use and technical operability of my website. These data are automatically processed when my website is accessed. Unless they are provided, you cannot use my services. I usually erase these data after seven days unless, under exceptional circumstances, I need them for a longer period for the above-mentioned purposes. In such a case we erase the data as soon as they are no longer required for the relevant purpose.

Contact form

You have the option of contacting me through a form.

If you use the “Contact form”, I need the following mandatory details (marked as such): first name, surname, email address, question.

I process these data on the basis of the European Union, particularly the General Data Protection Regulation GDPR Article 6 (1) point f. The purpose of processing your data is solely to deal with your contact request. In order to effectively handle your contact request, I will retain your data for up to six months. Any personal data that were additionally collected during the sending process are erased if they are no longer required for the purposes for which they were collected or otherwise processed.

Google Analytics

This website uses Google Analytics, a web analysis service of Google Inc. (hereinafter: “Google”). Google Analytics uses cookies, i.e. text files which are saved to your computer and allows me to analyze your use of the website. The information that is created by cookies on your use of my website is usually sent to a Google server in the United States, where it is then stored. However, if you have activated IP anonymisation for this website, your IP address will not be sent without first being truncated by Google within the Member States of the European Union or other parties to the Agreement on the European Economic Area. Only in exceptional cases will the full IP address be sent to a Google server in the United States and then truncated there. Acting on behalf of the site operators, Google will use this information to analyse your use of the website, to create reports on website activities for us as site operators and to provide us with other services connected with website and internet use. The IP address which Google Analytics sends via your browser will not be linked by Google with any other data Google may have.

This website uses Google Analytics with the extension _anonymizeIp(). This has the effect of truncating IP addresses before further processing, so that the data cannot be related to any specific person. If the data that are collected about you allow conclusions about you as a person, this is immediately prevented and the relevant personal data are thus erased immediately.

I use Google Analytics to analyze use of my website and to improve it at regular intervals. The statistical data I receive in this way helps me to improve my website and to make it more interesting for you as a user. For exceptional cases in which personal data is transferred to the United States, Google has subjected itself to the EU-US Privacy Shield (

The legal basis for the use of Google Analytics is GDPR Article 6 (1) point a, i.e. your consent. Any data that I send, and which is linked to cookies, user IDs or advertising IDs, is automatically erased after 14 months. Any data that has reached the end of its retention period is automatically erased once a month.

You can prevent the storage of cookies through a suitable setting in your browser software. Please note, however, that if you do so, you may not be able to use all the functions of this website in full. Furthermore, if you wish to prevent the collection of data generated by cookies and related to your usage of the website (incl. your IP address) and if you wish to opt out of such data being processed by Google, you can download and install a browser plug-in from the following link:

Opt-out cookies prevent any future collection of your data when visiting this website.

Further details about Google and its use of personal data can be obtained from the following addresses:

Map service

My website uses the map service OpenStreetMap, operated by OpenStreetMap Foundation (“OSMF”). When you access a page that includes OpenStreetMaps, your browser connects directly with the OSMF servers. The map content is transmitted directly to your browser and integrated into the website by OSMF via a so-called iFrame. If you do not wish OSMF to collect, process or use data about you via our website, you can disable JavaScript in your browser settings. However, if you do so, you will not be able to use the map display. Further details about data processing by OSMF can be found in the OSMF Privacy Policy:

Google reCAPTCHA

On this website, I use the reCAPTCHA feature of Google LLC, 1600 Amphitheater Parkway, Mountain View, CA 94043, USA (“Google”). This function is primarily used to distinguish whether an input is made by a natural person or abusive by automated and automated processing. The service includes the sending of the IP address and possibly other data required by Google for the reCAPTCHA service to Google and is carried out in accordance with Art. 6 para. 1 lit. f GDPR based on my legitimate interest in determining the individual will-bearingness of actions on the Internet and the prevention of abuse and spam.

Google LLC, based in the US, is certified under the us European Privacy Protection Convention “Privacy Shield”.

For more information on Google reCAPTCHA and the Google Privacy Policy, please visit:

If websites and services by other site owners are linked to this website, they have been and will continue to be designed and supplied by third parties. I have no influence on the design, content or function of third-party services, and I expressly distance ourselves from any content provided by linked third-party sites. Please remember that third-party sites linked to this website may have their own cookies which are installed on your device to collect personal data. I have no influence over this. In such cases you may wish to obtain more information directly from the owners of the third-party websites linked to this site.


I use cookies on this website to provide you with a better user experience. I do this by placing a small text file on your device / computer hard drive to track how you use the website, to record or log whether you have seen particular messages that I display, to keep you logged into the website where applicable, to display relevant adverts or content, referred you to a third party website.

Some cookies are required to enjoy and use the full functionality of this website.

Categories of cookies

I use cookies for a variety of purposes and with different functions. Moreover, I make distinctions between cookies, depending on whether they are mandatory from a technical perspective (i.e., a technical requirement), how long they are stored and used (known as the retention period) and whether they have been set by our website itself or by a third party and, if so, by whom (i.e., by which cookie provider).

Technically mandatory cookies: I use certain cookies because they are mandatory requirements to ensure that my website and its functions can work in a legally compliant manner. Such cookies are automatically set when the website or a specific function is accessed, unless you have prevented the setting of cookies through your browser settings. Any data collected through the use of such cookies are processed by us on the basis of GDPR Article 6 (1) point f.

Technically non-mandatory cookies: On the other hand, non-mandatory cookies are set to improve, for instance, the convenience and performance of my website or to save certain settings you have made. I also use technically non-mandatory cookies to obtain information on the frequency with which certain parts of our website are used, so that I can tailor them more closely to your needs in the future. I do not store technically non-mandatory cookies until you click the relevant box, confirming that you have read our cookie note, and continue to use our website. Any data collected through the use of such cookies are processed by me on the basis of GDPR Article 6 (1) point a.

Retention period

Session cookies: Most cookies are only required for as long as you access the current service or continue your session. They are either erased or lose their validity as soon as you leave my website or your current session has expired (these are so-called session cookies). Session cookies are used, for instance, to retain certain information during your session.

Permanent cookies: It happens occasionally that cookies are saved for a longer period of time, for instance, to recognize you when you open my website again at a later point. It means that you can call up saved settings again. This means you can access my website faster and more conveniently, and you don’t have to make certain settings again, e.g., specify the relevant language. Permanent cookies are automatically deleted upon the expiry of a defined period of time following the date on which you visited the site or domain where the cookie was set.

Third-party cookies: So-called third-party cookies are set and used by other providers or websites, for example by operators of web analysis tools. Further details on web analysis tools and range measurement can be found below in this Policy. Third-party providers can also use cookies to display adverts or to integrate social media content, e.g., social plug-ins.

Erasure of and objection to the use of cookies

The acceptance of cookies is not mandatory in the use of my website. If you do not want cookies to be saved to your device, you can disable the relevant option in the system settings of your browser. Saved cookies can be deleted through the system settings in your browser at any time. Please note, however, that if you do not accept cookies, the functions of our services may be limited.

Cookies that I use are:

Name of CookiesTechnical necessityLength of savingCookie-ProviderUse and interest
JKRCookieConsentNoPermanent Cookie (1 year)JKRThis cookie avoids the need to show consent at each visit
ga-disable-UA-86131633-1NoPermanent Cookie (31 Dec 2099JKRThis cookie prevents the tracking at Google Analytics for the property of
_gaNoPermanent Cookie (2 years)Google LLCThis cookie is used to differentiate users in Google Analytics
_gat_UA-86131633-1NoPermanent Cookie (1 minute)Google LLCThis cookie is used to lower the requests at Google Analytics
_gidNoPermanent Cookie (24h)Google LLCThis cookie is used to differentiate users in Google Analytics

Recipients of personal data

I only share your personal data with external recipients if this is required for managing or processing your request, if there is some different legitimate permission or if you have given me your consent for this purpose. External recipients may be:

  • Processors: External service providers I use for the provision of services, for instance for the provision of content. I carefully select such processors and regularly check them to ensure the safeguarding of your privacy. Service providers may only use data for the purposes I specify.
  • Public bodies: Public authorities and state institutions, such as public prosecutors, courts of law and fiscal authorities to which I need to send personal data for mandatory legal reasons.
  • Private bodies: Cooperation partners and assistants, to whom data is transmitted on the basis of consent or a mandatory requirement.

Data processing in third countries

If data are transmitted to bodies that have their head offices or data-processing locations outside EU member states and outside states forming part of the EEA, we ensure before disclosure that – except for certain legally permitted exceptions – those bodies either have your adequate consent or they provide an adequate level of data protection (for instance, through an adequacy decision taken by the European Commission, through suitable guarantees such as the recipient’s self certification for the EU-US Privacy Shield or the agreement of so-called standard EU contractual clauses with the recipient). You can request from me a list of recipients in third countries and a copy of the provisions that have been agreed in each case to ensure an adequate level of data protection. To do so, please use the contact details given above.

Retention period

You will find the retention period for personal data in the relevant chapter on data processing. I generally apply the rule whereby I only save your personal data for as long as they are required to fulfil their purposes or – if you have given your consent – until you revoke your consent. If you revoke your consent, I erase your personal data, unless further processing is permitted under the relevant applicable statutory provisions. I also erase your personal data if we are under an obligation to do so on legal grounds.

Rights of data subjects

As a data subject you are entitled to the following rights:

  • Right to information: You have a right to access the data we have stored about you as a person.
  • Right to rectification and deletion: You can require me to correct inaccurate data or – provided that the legal grounds are in place – to delete your data.
  • Restriction of processing: Provided that the legal grounds are in place, you can require me to restrict the processing of your data.
  • Data portability: If you have provided me with data on the basis of a contract or your consent, and as long as there are legal grounds, you can require me to send you the data you gave me in a structured, commonly used and machine-readable format, or you can require me to send your data to a different controller.

Objection to data processing on the legal basis of “legitimate interest” under GDPR Article 6 (1) point f: If there are reasons arising from your specific situation, you are entitled to object to my processing of your data at any time, provided that such an objection has its legal basis in a “legitimate interest”. If you make use of your right to object, I shall discontinue the processing of your data, unless I can – within the parameters of the law – demonstrate compelling legitimate grounds for further processing, outweighing your own rights. To make use of your right to object, please use the contact details above.

  • Objection to cookies: You can also object to the use of cookies at any time. You will find the relevant details in our notes on cookies.
  • Revocation of consent: If you have given me your consent to the processing of your data, you can revoke the same at any time with future effect. This, however, does not affect the legitimacy of processing your data until the date of revocation.
  • Right to lodge a complaint with the supervisory authority: You can also lodge a complaint with the competent supervisory authority if you believe that the processing of your data has breached the latest applicable law. To do so, you can contact the data protection authority responsible for your place of residence or country or the data protection authority responsible for myselves. See BfDI

Your contact with me: In addition, if you have any questions about the processing of your personal data, your rights as a data subject or any consent you may have given, please feel free to contact me without incurring any charge. To exercise any of the aforementioned rights, please contact me as specified above. When you do so, please make sure that I can clearly identify you.

Update status

The latest version of this data protection statement shall be applicable. Last updated: 24 December 2019.