Whirly
We flew last summer from EGHH to Bad Durkheim (EDRF) near Mannheim, via the ubiquitous stop at L2K for fuel. Can't help much with comments about weather in Southern Germany as we did not go that far, but a few observations on Northern France and Germany as I found it. We flew out on a Sunday and back on a Tuesday afternoon.
During the weekend, a large number of the French DA/RA seem to be inactive. There is one long one which we had to cross, but checking in the SIA VFR guide showed that during the week it was only active to around 1500 so we were OK.
I crossed one or two of the other DA during the return and the controller at Paris North FIS was reasonably helpful giving be the details of Cambrai Approach - who seemed mainly interested in how many people were on board - however we eventually were cleared to cross just as the boundary was approaching (GPS is wonderful at times like that!)
Germnay was much easier - no issues with silencers for me at Bad Durkheim and landing fee and parking for three days of 5 euros. FIS from Frankfurt was excellent - above about 3500 feet they gave me a sqawk and provided a radar service which was excellent
"G-TY traffic information for you is a 747 climbing out of Ramstein" and the like.
Overall I felt the controllers in Germany were more helpful than the French, but that could just be me!
I used the SIA VFR kit for the whole trip as the map went far enough into Germany. Overall this was not bad, with a reasonable portion of the handbook in English (useful if like me you can speak some German but very little French!)
Hope this is some use to you.
TZ