Île des Morts is a 7-hectare island in the Bay of Roscanvel, to the south-west of the roadstead of Brest, between the Quélern peninsula and Île Longue. It is 26m above sea level at its highest point.
Wikipedia https://en.wikipedia.org/wiki/Île_des_Morts
Coordinates 48°18'11.302" N -4°32'14.172" E