Language courses at uni?Watch
However, as a linguist you should be able to adapt to other languages quite easily so if you are drawn towards another language then I'd say there's no harm in picking it! You should do some research into the course for each language, what you'll be studying. Also look at the culture of the country and listen to people speaking it. I think that will help you decide.
Finally, what do you want to do with your degree? If you want to live in France and work there then it's obvious that you should study the language but if not then you don't have to.