Hi All
Another site near Troyes well worth considering is at Geraudot -on the nothern side of the Lac de La Foret d'Orient. The site is just back from the lake along a lane on the other side of the road around the lake. Like most french sites, booking is not required, except possibly between 14 July and 15 August. This is a mixed 'staying' and 'transit' site, so even then you should not have problems if you arrive reasonably early. There are some good walks/cycle paths around the lakes. See page 384 of Caravan Club Europe 1 (2009).
While in French mode, there is also a gret little site just a bit futher north, near Vitry le Francois - Aire Naturelle Camping Nature - at Luxemont-et-Villotte, see page 751 of CC Europe 1. A small CL-type site, with fishing/swimming in a nearby lake and walks/cycle rides on a canal towpath or around the nearby Lac de Der.
Cheers
Paul