I don't know if this will become a March tradition, but for the World Water Forum, the city of Marseille had an amazing Mediterranean themed carnival parade at Parc Borley - giant mermaids, hydraulic stilt walkers, dancers, acrobats, and pirates clearly representing a wide swath of schools and organizations throughout the city. Bands and activities continued into the late afternoon. Might be worth inquiring when and if the next one might be planned before you schedule your trip.
The park itself is lovely - there is a beautiful creek to the nw and the beach to the south, gardens to the east. Families and friends frequent it throughout the weekend especially.
Straight east of the park to the first roundabout, about 2 miles east, you will find a nice suburban mall and cinema too, will a super-walmart type French dept. store/supermarket, which cheese aisle alone and to-go paella were equally amazing attractions for me.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.