Day 0: Frankfurt (landing)
Day 0,1,2,3: Amsterdam
Day 4,5,6: Berlin
Day 7,8,9: Prague
Day 10: Frankfurt (event planned)
Day 11,12,13,14: Paris
Day 14,15,0: Frankfurt (departure)
frankfurt-amsterdam: via ice: 3hours 42min
amsterdam-berlin: via ic/ice: 8hours
berlin-prague: via EC: 5hours
prague-frankfurt: via?: 7hours
frankfurt-paris: via TGV/ICE: 7hours
paris-frankfurt: via TGV/ICE: 7hours
is everything matching up here?
You've allowed multiple days in every location (except day 10), that's a good thing.
Looking at the map, there's a good bit of zig-zagging west, then east, then west again. But this may be unavoidable, given the constraints of flying into and out of Frankfurt and an event planned requiring you to be back in Frankfurt on day 10.
It looks like you have 4 days of your trip on the train. For the FRA-CDG round trip, look at airberlin.com and you will probably pick up an extra day. Also, look at flylc.com which shows low-coast point to point airlines that are not on Orbitz, ect. When you find something there, go to the airlines' website to book.
Good suggestions from Jerry (above post). A rough rule of thumb used by some experienced travelers in Europe is: if the train is going to take longer than 6 hours, consider flying, depending on the airfare (including likely baggage charges) and other factors, such as airport locations (is the airport a small airport requiring extra transportation cost to get to the city center the train would probably automatically take you to).
