That's why I never fly that low. Take off and go straight up to at least 2000ft.
Illegality aside (and that you*tube video is an incredibly stupid thing to go public with because so much of that flight was not just under 500ft from people but more like under 20ft in some cases) one can understand why they fly so low: it is a lot more exciting.
Flying a paramotor at 2000ft, not only is the ground barely moving (it is only barely moving at 150kt as far as I am concerned, especially over
N France 
) but you will be going backwards a lot of the time