Poulpy, you can do better than I at finding sources for media in France, since I don’t live there and don’t speak French, but here are a few sites either in France or that ship to France:
I don’t know anything about the first three sites. The last one, Meritline, has a mixed reputation in America - some people love them, others complain about their packaging and return services.
Of course, you will pay extra for international shipping from the companies not in France or Europe (expect to pay around 20-35 US$), and I assume you will still be responsible for the VAT when it arrives at your end.
These links are probably best just for giving you some idea of what is out there and their relative prices. On sale, we can get 100 TY discs in America for $10~$20 in retail stores. But the inkjet printable TY media (which can usually be found on-line only) generally go for $35~$45 per 100. I suppose you might see the same price premium in France.