If travel has increased to pre-pandemic numbers just by my observations and perception , good. Regardless, I choose the itinerary based on mainly interests and singular recommendations by locals.
Luckily, I have received numerous such recommendations in Germany and France concerning small places...Barbizon, Montmirail, Vimy, Compiegne, Noyon, Bar-le-Duc, Amiens, Toulouse, Fontainebleau, and so on.
My first 3 trips in the 1970s began with going to big urban centers as well as small towns: London, Vienna, Paris, Hamburg, (west) Berlin, Munich , Frankfurt, Prague (cold war days), etc, plus the smaller and less visited cities , Bonn, Sigmaringen, Lüneburg, Dortmund, Lübeck, Friedrichsruh bei Hamburg, Wetzlar, Münster/Westf.
Obviously, the political situation affects my choice of places to be visited. Your itinerary is dictated by that too. The fall of the Wall opened up for me numerous places in eastern Germany I wanted to get to and explore, yes, after 30 plus years, I still have yet to visit them ....Greifswald, Prenzlau, Schwerin, Stralsund, Erfurt, Leipzig (especially) , Naumburg an der Saale, , etc, etc.
Thankfully (based on recommendations by locals) and luckily too, I have managed to get to numerous smaller places in eastern Germany visiting once, twice, ... , such as Neustrelitz, Küstrin-Kietz, Wustrau/Brandenburg, Potsdam-Babelsberg, Magdeburg an der Elbe, Neuhardenberg,
Bottom line: My trip this summer , above all, the France part , has factored in numerous smaller places visited primarily by French tourists... Cherbourg, Grenoble, Chaumont, towns on the Aube River, and in Lorraine using Metz as a base,
If one wants to avoid being swamped by international tourists in the summer, go to the towns visited almost exclusively by local tourists, tons of places fit that bill in all of Germany and France.