No local French schools in the Flemish provinces, with the exception of the "facility" communes, Wezembeek-Oppem and Kraainem for example, but you have to live in these communes to be eligible for the schools there. The nearest French schools are in Brussels, Joli-Bois, Stockel, Mater Dei and Sacré-Coeur de Stockel, but too late for enrolment for next school year at the latter 2, perhaps Stockel too. International Montessori do "bilingual" French/English and it is fee paying in Tervuren. Kleuterscholen in Tervuren are GBS Tervuren, Koninklijk Tervuren (think called Kattensprong), Mariaschool, all fairl close to the centre, otherwise Catholic one in Duisberg, gemeente ones in Moorsel and Vossem.
You need to ask Tervuren gemeente or your notaris regarding rules not speaking Flemish as people have been refused purchasing property in Flanders when deemed to have little "connection" with Flemish culture. However, Tervuren has a host of nationalities who own property there, I wouldn't be overly worried about a negative response.
Plenty of stages for the holidays, start at 2 years old, tends to be little more than child care at that age, too many to mention in French, nearest in W-O and WSP. In Dutch, ask at the Gemeentehuis or at a local school, or at the sports centre or swimming pool, there will be adverts up for them.