Someday on the German Autobahn I was close to running on empty (my mistake), so had no other choice than to 'accept' some biofuel at the nearest fuel station (contains ethanol). Not particularly amused and only took a minimum to get me to the next Shell station where I got a full tank of Shell V-Power 100.
So, when driving through Germany, take high octane fuel (98 and more) each time you have less than a half tank. No worries by doing so.
