Someone say it's Orange, but I don't agree.
I think the best French provider is SFR.
Orange upload speeds are not great, while with SFR streaming is much smoother.
I'm from France, all providers have a low upload speed (worse than Italy) if no optic fiber
Numericable has the best upload with 500kb/s but the number of dreambox is terribly low for an huge range.
You can see their upload speed on
I got my upload ISP upgraded from 1MB to 7MB since 1st November. I can upload vids faster