I do see Lapwings every so often in the Poitou-Charentes region but on this visit I have seen some big flocks of them. They are probably what are known as passage migrants. Which means just passing through.
There will be some residents but large numbers like this will be caused by migrants.
The reason for this long journey is that in North western Europe they will find conditions better suited to successfully raising a family. (Longer periods of daylight so they can work 12 or more hours a day providing food for their young)
They will move through several countries in their migration, moving steadily northwards mostly travelling during daylight hours. They will have come from countries as far away as north Africa, northern India and Pakistan.