Help with Itinerary- Paris, Normandy, Austria, Prague?

You will be all over map but if that's what you want it's doable. Fly from Paris to Prague. Then go by bus or train to Cesky Krumlov. From there by shuttle to Salzburg. From Salzburg either to Vienna or Munich and fly home from there.

For information on your options about getting between any two places, a great start is Rome2Rio: http://www.rome2rio.com/. However, the prices they show don't reflect the possibility of advance purchase discounts.

To actually see flight prices, try Skyscanner: http://www.skyscanner.com/

Salzburg has its own airport, but Munich airport is not too far and gets many more fights.

For train schedules for almost all of Europe, use the Bahn (German Rail) website http://reiseauskunft.bahn.de/bin/query.exe/en, following Rick's tutorial: http://www.ricksteves.com/travel-tips/transportation/trains/online-schedules

This website will only have prices for trains that start or end in Germany. To buy tickets at the best price, you almost always want the operator of the train. Here's a great list, from the train guru The Man In Seat 61: http://tinyurl.com/bo8x6o6

Have fun researching!

From St Malo continue on to Nantes for a flight to Prague (perhaps via Paris CDG or Amsterdam).
It's an easy train ride from Prague to Salzburg, and then to Munich for flights home.
You could also include Vienna if you wished.