Learning foreign language like French or German is a good idea, they are going to be considered as an additional qualification. Those institute used to train their own language as part time or 1 to 2 hours class per day which helps to know the basic to advanced level of the language. There are courses in different level (beginner to expert) which each of them have duration of 3 months with certification program.
Once you go through the training and complete the test/exam, you will then get its certification along with additional language expertise, pronunciation, letters writing style, in-depth grammar knowledge plus other culture and their general knowledge etc. You will definitely get assistance from their own institute to get a good Translator or Interpreter job, you can even work as Freelancer for foreign language, you can put online ads for Language assistance where many star hotels, tourists and other concern organization will contact you for related job.
You can contact those institute directly for more detail on this topic. To learn French language in Chennai, Alliance Francais Institute is one of the best in College Road, Nungambakkam, Chennai.