Spent 2 weeks at Les Mimosas in July/August, 2 families with kids aged 5 to 8.
We enjoyed our stay, but if it were not for the pools (the best we have seen) and a primary reason for going, then the site would have disappointed.
The things we liked were:
The aforementioned pools, they really are superb. Limited queues and a great selection (not sure why they are closed for 2 hours in the middle of the day though), the wave pool was a big hit with our 5 and 7 year olds. Unlike most French sites, getting a lounger was not too painful. Slightly frustrating that you can not eat anywhere near the pool, meaning you had to buy food from adjacent pool cafe (picknick not allowed) which doubled up as smoking area.
The toilets blocks were great, lots of hot water and clean.
The staff were superb and the site is well maintained and cleaned.
Fridge hire was excellent.
Not many English (may or may not be your thing). Lots of French, Belgians and Dutch.
Good location - easy for bike rides along the Canal Du Midi, but it takes a car ride to attractions/beaches.
We preferred the quieter Portiragnes Plage, Valras Plage is bigger as is Vias Plage (tough to park and a bit like Blackpool).
A decent Carrefour that is 5 mins away and open 7 days a week.
The things that were not so good.
Our pitches (we were 2 families). Despite asking for shade, we got none and the pitch surface was very up and down. Ours had huge craters in it. Both were smaller than average when compared to neighbours.
The shop - selection and prices were very much the usual, but closing from 1230 to 5 is excessive in my eyes.
Play park - quite small and not opening till 930
Bar the main route, the roads are all gravel/stone. It meant that if our 5 year old wanted to ride his bike, then he had to be on the main thoroughfare, which was not unsurprisingly busy.
We had a great stay, but the pools really saved it. It is our first 4 star site, but I think we will return to 5 in 2016.