I have French nationality since birth (born in 1991). However due to various reasons, I have an Indian passport and no French passport. I have not traveled outside India with my Indian passport either. I need to understand the process to surrender my Indian passport and obtain a French passport.
That's two, non-related, processes. If you are indeed French, you can apply for a passport at the nearest French consulate. You'll have to go there, you can't do this by post - they will take your fingerprints.
As for renouncing your Indian citizenship, it is not required by France. And, more importantly, if you're planning to stay in India, you would need a visa. Better keep your Indian passport as long as you live in India. You would need it too, to exit India - for India, you're an Indian citizen, and there's no French citizen living there with your name.