Very happy to share that @mediapart now has an Onion service, accessible at https://www.mediapartrvj4bsgolbxixw57ru7fh4jqckparke4vs365guu6ho64yd.onion
You can find the full annoucement in English here: https://blogs.mediapart.fr/mediapart-journal-independant-et-participatif/blog/050924/mediapart-launches-tor
Many thanks to the @torproject for helping us in this process. I have done a small technical interview about this, available on their blog: https://blog.torproject.org/mediapart-launches-onion-service/