Far easier than between UK and FR ...
But I have a question/doubt about your general planning: did you intend to make Villerupt LFAW your first landing on the continent? That is not going to work: you need to land at a field with immigration (also but incorrectly known as a "customs field"). Villerupt is certainly not one of those, and indeed it seems you cannot land there at all : "AD reserved for home based ACFT and ULM, and those based on neighbouring" says the official SIA doc. But perhaps there is a local work-around?
BTW will you be flying IFR or VFR?