What language did Claude Monet speak?

he has a European accent.

*the person means a french accent*

He spoke French - is that an accent?

He spoke French and had a french accent. Yes, french is an accent as well as a language.

Example: If I say I have a french jacket, I mean that I have a jacket that is from France. When I mentioned that Monet had a french accent, I meant that he spoke french with the accent of someone who is from France, versus, let's say a French-Canadian, Haitian, Belgian accent, etc...

An "European accent" doesn't really mean much because there is no such a thing as an European Language. Many languages are spoken in Europe, as well as multiple countries that speak french (France and Belgium) and the language that Monet spoke was French, with a french accent.

Hope that sounds more clear now.