Hi,
I'm in charge of the most decent TCG website in France,
Pokécardex. You may call it a Pokegym-like. There are no real "official website" for French OP, the local distributor just gives to the community what they need.
I'm also a player and a league&tournaments organiser.
The league repartition is mapped
on this topic (old map, but it changed just a few). There is at least 1 BR (both autumn and spring) for each league, something like 20 BR A for the coming season, 5 Regionals, 14 Citys, and for the next Regionals and BR we'll see.
Leaving near the North-East of Paris (or just North-East of France), you'll get the biggest part of the tournaments.
Compiègne is the most active place, thus the biggest tournaments are often there or close to that city.
For the South of France, there are still leagues and tournaments (refering to the map), but you could need to travel more. I live in
Antibes (near
Nice), the current year I travelled to
Montpellier,
Lyon,
Lausanne in Switzerland, and
Milano and
Torino in Italy (did it thanks to my favourite car driver).
If you have any questions, go ahead.
Also, where will you be in France ?