The Beach close to Calvi is loooong and offers plenty of little bars and restaurants attached to it. It also has most of the attractions like wake boards, banana rides etc. that you usually have at a tourist beach.
In this category it's still nice as it's quite relaxed still, at least in end of may where i've been there. Although i heard you shouldn't go there during nights as it is supposed to be a bit dangerous with drug dealers, i still really like to hangout there.
Look at Calvi and the Ships going in and out of the Harbor. It has beautiful sand and the access is very slow you can take children and let them play near the beach in the water.
During the week the legion etranger is flying past the beach and drops parachutists all day where one can watch. It's a nice spectacle while lying lazy in the sun ;). read more