17 days beginning in Barcelona Ending in Paris

What time of year? That will affect the suggestions. And why only two days for Paris?

I would spend some time in Carcassone, Avignon, and possibly Lyon.

What time of year are you traveling? If you have never been to Paris, two days is just not long enough. I would take at least two days from your other locations and add them to Paris. IMO, 4 days is the minimum for a first trip. I haven't been to the other places you mention, but I can't imagine why they should rate so much more time than Paris. I have spent over two weeks in Paris and have still not seen everything I want to see.

Nanci: The most obvious problem I see with your plan is that you are combining 4 destinations very difficult to link, especially in 17 days. A similar trip in the US (using roads, not trains) would be something like Tucson[INVALID]Sacramento[INVALID]-New Orleans[INVALID]finish in Salt Lake City. My suggestion would be to drop the Basque country (San Sebastian). Fly into Barcelona and do 3 days after arrival day. On Day 5, fly to Nice (if a discount airline can be found) or train from Barcelona to Narbonne/Perpignan/Marseilles, overnight. Next day train to Nice, 5 days there. (I assume this is a summer trip?) Then TGV to Paris and 5 days there, flying home out of Paris. The other posters are absolutely right about 2 days for paris being too little. The time of year matters too, as seaside resorts are less appealing in the winter. Since you are, as you say, completely new to Europe, may I make another suggestion? Why not do three cities: London, Paris, and Barcelona flying "open jaw" into London and out of barcelona, Eurostar between London and Paris and discount airline Paris to Barcelona. Divide your time equally among these (perhaps a little less for barcelona) and you would have a wonderful trip. You could easily do daytrips out into the countryside to vary the city experience.