We are transparent about this, the answer to your question is in our legal notice (where you can opt-out the tracking, by the way).
In order to adapt the site to our visitors’ requests, we analyze the traffic of our sites with Matomo. Matomo generates a cookie with a unique identifier, whose storage period is limited to 13 months. The data collected (IP address, User-Agent…) are anonymized and kept for a period of 6 months. They are not transferred to third parties or used for any other purpose.
Furthermore, tracking is not active if your browser is configured with the DNT (DoNotTrack) option.