Jacques-I always try to help you if I can, but it is not my regular language. When I use google translate French to English = Phare de travail = Working light. 

I looked at qualitydiecasttoys.com. The description at Dinky 1412 that light is called there as searchlight. British members, please react if this is correct.

Kind regards,

20-5-2017 Jan Oldenhuis

In the States, at least, we call such things a "work light." One could also call it a "searchlight" or a "spotlight" but I think those terms refer more to a lamp that can be aimed and intended to operate over a distance, whereas a work light more likely has a fixed focus and is aimed at the area right behind the vehicle.