Often I find it very difficult to understand people from France speaking English (I don't know any French Canadians, so I don't know about them). Their accent is not only very strong, but it also obscures many of the consonant and vowel sounds for me. Other nationalities, such as Greeks, Italians and Spaniards (count me in!), also have very strong accents (i.e. very noticeable) in English, but the words are clearly pronounced and it's easier for me to understand them.