You born in French colony of pondichery your grandfather had French nationality can you get French nationality?

The treaty giving back the French colony of Pondichéry, to India came into effect in Aug. 1962. Under the terms of the treaty, the people living there had a six-month period to make a choice between either the French or Indian nationality. The people who did not express their willingness to gain French citizenship were automatically given Indian citizenship at the end of the 6-month period.

You can claim French citizenship ONLY IF your father, specifically requested French citizenship at the time meaning that he is/was a French citizen.