I'm fluent in english, french and german. I'm installing Syberia, but I don't know which language I should choose!
I know it's a french game, but maybe they had better voice actors or a bigger budget for the english version (I think I can rule out the german one).
Did anyone have the opportunity to compare? General reviews of the voices in german, french or english would be helpful too.
Thanks in advance!

I have an English-only download. The voice acting is fine, especially Kate's voice artist. The rest of the cast is mixed, some good, some passable, a few oddities here and there that are the result of recording without animation to follow. I found it very enjoyable on the whole.

My only complaint about the English version is everyone except the American characters has a British accent of some sort. It kinda makes the parts of the game set in Russia, Germany and France just look silly.

That's true. The range of accents in the English version is severely limited. It's not a directorial choice that I prefer, but the acting itself is generally fine. Low-key, nothing spectacular.

German voices are fine. Maybe you should try to find some Let's play in different languages on youtube and watch the beginning to check Kates different voices.