Surely a small FR base at either NCL, MME or LBA would work to many of the current pile of FR destinations, ie TFS, MAD, SXF are 3 that come stright to mind.
I'm surprised they've never tried HHN, to take advantage of the foolhardy travellers who run the gauntlet of booking 'connecting' flights with FR.
In fact, it seems strange that there are so few flights to Germany (on any airline). You would have thought that when Newcastle can support such esoteric destinations as Galway and Stavanger, that a link to MUC, FRA or BER might be a goer.