No idea. I'm pretty sure he was not born in Paris though, he just lives there now (well, not now, because he's in ancient Egypt). I remember reading somewhere (not official, though) that he was born in America, which makes sense: he has an American accent, raccoons are native to North America, and he was raised at the Happy Camper Orphanage (English, not French). Related to this, but in no way a confirmation of where he was born, McSweeney turned himself in and is currently in an American penitentiary, Heathrow. This likely means that McSweeney lived in America previously, and he was part of Conner's gang, so...
Again, I'm pretty sure there is no definitive answer, but if I was a betting man, I would put money on him being born in the US.
The only other reason for you to be speaking American in a different country is if you've focused too much on a lot of American stuff like shows, movies and most of all games.
Like Dimitri. With music videos, anyway.
Yeah! Like him. He's lived in Paris his entire life while watching a lot of disco music videos.
But still, he has some accent. In fact, may characters have different accents
You're right, they all speak english (except Shamen & Caveman) but they also have accents depending on where they're from.