I read an article somewhere some time ago (unfortunately, I can't find it) that said it had been proven by some studies that French speakers were predisposed to suck at pronouncing foreign languages and this was something to do with French having so few sounds (or maybe there was something about frequencies or whatnot) we just couldn't hear other languages correctly and therefore couldn't pronounce them either. I don't know if this is true, but I must admit it could be. Almost every French speaker I hear speak English has a very thick accent (including myself, though I'm not the worst), whereas I hear people with other native languages speak English almost flawlessly. Why?
French does, I think, have a sort of oddness to its pronunciation that isn't shared by other European languages (or even other Romance languages). This is evidenced by the fact (as I learned in music history class) that, when opera (which originated in Italy) became popular in France and composers began writing French operas, they had to invent a whole new style of aria because what worked in Italian (and even other languages like German) just didn't work in French.