My apologies if this is the wrong place for my Q, as my search of FT did not reveal a FRA forum per se, and I thought LH FF'ers would be likely to know the answer.

A few years ago, twice, when I returned a rental car at FRA it was very difficult, poorly signed, and I landed up going in circles quite a bit getting nervous about missing my flight, and having to stop at a curb and ask a traffic guard where to go.

I have not returned a rental car at the FRA airport in a few years ( have either been just connecting in FRA to other cities, or taking a nice train in, no cars) but I will be flying FRA-IST out of Terminal 1 on LH in a couple months and I do not want to get lost again or waste time when returning my car the morning pre-flight ( I am renting the car originally in Koblenz). The FRA PDF map on the internet is not that helpful, ( Europcar, my rental company this time, and any rental car return site for that matter is not on the map for returns, only for initial rentals)and Europcar and FRA discussion websites just say follow signs to P1,2,3. Some people on travel sites on internet have said, 'watch out! poorly signed, easy to miss.' I am hoping to do better than that in my planning. Any tips would be appreciated. Vielen Dank in advance!
I will be coming into FRA from the direction of Koblenz, if that makes a difference.