The legend

The banners that are wound around the three winged stags bear verses in Gothic characters.
The central one, which winds around the flagpole and between the large stag’s wings, bears four veress encouraging the loyal French to stay true to the flag bearer (i.e. the king of France), and therefore not to defect to the English side:
C est. estandart / est. une enseigne
Qui. aloial francois enseigne
de jamais ne la bandonner.
s’il ne veult son / bonneur [honneur] donner

The left banner claims the victory of French weapons, and therefore the French king, in battle:
Armes. porte. très glorieuses.
Et. sur. toutes victorieuses.

Finally, the one on the right extols the praises of these arms:
Si. noble. na. / dessoubz. les cieulx
Je. ne. pourroye. / porter. mieulx