Let's See What Happens

Do you have specific plans for Frankfurt? If not, I’d try to minimize the time there and spend more time in both London and Paris — 3 days is pretty much the minimum, IMO for each.

I would put your time in Frankfurt at the end of your trip by taking the train directly from the Frankfurt airport to Paris (connection in Mannheim) upon arrival. Look for a cheap flight from London back to Frankfurt.

Have you looked into an open jaw flight for this?

This is the curse of Frankfurt: the city is boring as hell, but it’s cheap to fly to. I’m guessing you got a good round trip flight for a good price? Well, fly in and get the hell out and add a day to London and Paris like OL suggested.

Definitely, that’s what I’m doing. I’m flying out of Frankfurt to go to Asia, which is why I had to fly IN there, too. I’m spending only one day there and devoting more time to Paris and London

Cool!