Con, that looks like Vianden to me. It has an absurdly fairy-tale castle (real medieval, restored in the 1960s). Could also be reached in c. 15 min from Prüm.
Also, if you come from Prüm you should also have heard of the Echternacher Springprozession (two steps forward and one step back, the Germans say
) . My village band plays in that.
(That is not our band, but a neighbouring village.)
It is practically impossible to find a pic with both bands and dancers, so here are some of the dancers performing one of the two steps forward.