In reply to lattakikk:
I'm not sure of the northern sectors for kids height-wise, but Canche aux Merciers and Potets, both in Trois Pignons have either EN, yellow or orange circuits which are reasonably low for the best part (i.e. plenty of 2-3m high blocs).
The orange at Cul de Chien is a goodun also, although a few blocs may be high for kids. Much of the orange at Isatis is a delight, but it is mixed up with highballs, although the majority are at the 2-3.5m height.
As for people saying there is a lot of polish. From 2017 up to lockdown and once last year I managed 14 trips to Bleau, climbing over 1000 problems f6a and below. So many starts require good feet but I've rarely found polish to be the issue, just me. I do acknowledge there are a few exceptions.