French player here.
Pathfinder being older, most of its wiki has been translated to French. You can find it at www.pathfinder-fr.org. Some entries are poorly translated or missing but they're very rare.
As of now, I've yet to find a good site with a D&D 5e translation. There is also less content published, so the percentage of translation may be higher.
Blake Steel suggested this search in dmsguild, filtered by language.
Books and availability
All base books of Pathfinder have also been fully released by Paizo in French, as well as most Adventure Paths, and can be found in your local (well-furnished) game store (thanks @BlakeSteel for the reminder. List includes but is not restricted to: Core rulebook, Gamemastering book, All bestiaries, most extensions and all AP i know off)
The base book for D&D 5e can also be found, and are just as available, if not slightly more (by a short margin - You can also find D&D 5e in general bookstore chains, such as La Fnac, to name one. P&P RPG being popularized, they try to have some rulebooks, and the most famous is obviously D&D5e. You won't find any extensions, though, you will have to go to a specialized seller).
Thanks to Blake Steel for the list of 5e localized products announcements.
Since you were starting, I pointed first at online resources, assuming you would not invest just yet.
Overall, out of experience, Pathfinder is more easily available than 5e in France, and you can find more translated content, just because it's older (and therefore, translators have had more time). Easiest (and cheapest) way is online, you'll have to order or find a good game shop if you want to invest in physical copies.