For the first time in a very long time, longhaul J is available at 50% off in the Promo Awards.
Fort-de-France (Martinique), Point-à-Pitre (Guadeloupe) and Saint-Denis (Réunion) are available in AF J at advertised rates of, respectively, 38k miles, 38k miles and 49750 miles.
These appear to be the price when departing from PAR; departing from NL/DE/elsewhere in Europe brings the cost down. The first two routes are both available from 32.5k each way, 65k return from e.g. AMS. Available dates are relatively poor. There's nothing on the Pointe a Pitre route in August, September or January, for example.
I could find no availabilty at the advertised Promo rate for Réunion from AMS; however, it shows up as available on only 3 dates in August for those departing directly from PAR:
So: the lesson is, it pays to be flexible in looking for an origin to benefit from these promo awards!