it is not readable https://www.mapillary.com/app/user/LoReninge?lat=50.9191653&lng=2.7882277&z=17&pKey=727847019358654&focus=photo&x=0.5777964212457156&y=0.505476887099974&zoom=1.619896133193123

However I can confidently guess it is a motorvehicle destination only sign.