Bonjour -
Great question! It's not equivalent to any college degree. The C2 (and all the other levels) are a measure of language proficiency. C2 indicates that you have near-native ability in the language, which means that you've studied it for, very approximately, 1,200 hours. You can read more about this here: https://www.french-test.com/blog/what-is-fluency/
what Is diploma C2 equivalent to? is it a degree or mastres degree? please I look forward to your feedback. My employer wants to know.