We were in Le Marin last winter when we purchased our SM. The previous owners signed a 6 month lease for a slip on Pontoon #4, just before we bought the boat.  We took over the lease with an agreement from the marina.     Our lease said electric was "included to 4%."    We were plugged in and ran everything except the air conditioners.  When we left there was no charge for electric and a modest charge for the water usage.   Last year the water was billed at 9 euro per cubic meter, or per 1000L.  

Martinique is great,  try the restaurant on the side of the road in St. Anne called Otantik, you will be impressed..    In the marina we found Oble Noir and Kokorum, were very friendly,  not so much L'Annex unless you speak French...well.

    Regards,   John

SV Annie  SM 37

Key West, Florida