Rocher des Potêts
This is a very old area, developed very long time ago. The boulders are mostly very low and it's one of the most family friendly areas around, still not super crowded. Not crowded because there are not so many developed harder boulders. The area features a huge amount of blocks that children can climb on but are not directly "established" problems.
Also you will find two circuits here. An orange AD circuit, 1-36 long! This one has some really really cool classics on it. Besides this one you'll find an Yellow PD circuit, 1-47 long (47 is marked A), this one has been re-drawn lately and changed a bit. The circuits are not going the same way around, but one could basically start with the orange, and continue with the yellow for a mega day.
Besides circuit problems you have some harder climbs as well here, and for the ones with the "developing eye" and a brush, you could easily brush up and make harder problems here and there. Mostly sit starts though, because of the height of the boulders in general.
You can easily reach the area with a stroller, so very family friendly, and obviously this is also a very good area for beginners or a rest day activity making an easier circuit.
The reception can be a bit bad, so downloading guide for offline use is recommended.