Lagering a Biere de Garde

[MarylandBrewer]

Wondering how long to lager (say at ~35*F) a Biere de Garde. Had 4 weeks in the primary using a lager yest (Bavarian) at a rather warm 60*F. Produced the esters/fruity aromas i wanted and now to age a bit. Does 4 weeks sound reasonable?

Thanks,

Allen