This is more of a language usage question, but since I can't think of another SE site where this question would fit, here goes.
English is the only language I know of that uses title case as opposed to sentence case.
Some specific examples for the languages you asked about:
Gaelic: Ceud soiridh soiridh bhuam (A Hundred Greetings from Me)
Breton: Amañ pell diouzh an trouz (Here Away from the Noise)
French: Quand on n'a plus rien à perdre (When You Have Nothing Left to Lose)
I suppose it would be ideal to have some resource where languages were listed with their capitalization style. Failing such an easy list after some quick Googling, I found another SE answer that links to Microsoft's style guides per language where you could check the "Capitalization" heading for any that you're interested in. For example, I just checked Dutch and Basque and they're also sentence case.
I think European languages all use sentence case, though I'm open to a counterexample. You might also find it interesting that some languages have no case, such as Arabic and Hebrew.
As jlliagre notes, French has more specific conventions that sometimes override sentence case (and even the question of what the first word is can be ambiguous when you begin with d' or l'). I suspect other languages do too — a well-known one is that German always capitalizes nouns — but all are likely set against the backdrop of one of the major case conventions.