You should contact Air France (or your travel agent, if you booked indirectly) and ask for the ticket to be changed.
I looked at the Air France fare tariff and the price of Bangalore-Culiacan is calculated in exactly the same way as Bangalore-Mazatalan. So I would not expect the price to change, although if your flight is in the near future I may be wrong because flights will begin to fill up.
Depending which fare you purchased, there will be change fee, which again from skim-reading Air France's tariff guide, I would expect to be 5000 INR or less.
Your alternative is to collect your bags at Mexican customs in Mexico City and then abandon your onward flight. I would not recommend this because the remainder of your ticket (including the return flights) may be voided.