How is Canadian French different from French spoken in modern France?

Really the biggest difference is just the accent. The accent difference is fairly strong. Just as somebody from New York City might have a pretty tough time understanding someone from a small town in Scotland, people from France sometimes have a hard time understanding us. There are a few words here and there that are different (like how in England, an apartment might be referred to as a flat- those kinds of differences), but spelling, grammar and everything else is the same.