Here is a recent thread on the same topic, you might find some helpful info. Unfortunately my trip got canceled at the last minute so I can't share advice based on what I ended up doing.

http://www.fodors.com/community/europe/day-trip-from-paris-via-train-would-like-to-incorporate-wine-tasting.cfm

Thanks, Sidny! Believe it or not, I did a forum search to make sure that I wasn't asking a question that had already been asked, but I somehow missed your thread. There is lots of good information on there. I'm so sorry you had to cancel your trip!

A friend and I did a day trip from Paris to Lyon. Had lunch, did a quick tour of the city and took the TGV back.

Nice outing.

Here's a simple link for day trips. http://www.thereareplaces.com/places/bestplaces/france/paris/daytrips/chantilly.htm

The Chateau du Chantilly is a trip. Remember the James Bond film, the world is not enough? It was partially filmed at the Chateau.

There is also famous horse racing here. I went one year to the Grand Prix du Jocky Club. Lots of fancy dress, mostly from England. It's the only time I've heard announcements in English in France. One of my favorite day trips of all time.

Thanks Whit. The way I look at it is, had I gone, the trip would be just a memory at this point. Now I have the rescheduled trip to look forward to!

Since your trip is several months away, you might want to keep in mind that the TGV opens the schedule for booking 90 days out and that is when you'll find the least expensive fares (Prems, I believe). I was a bit shocked at how expensive some of the last minute fares were for destinations only an hour or two from Paris.

You might look at this thread for day trips closer to Paris that don't require TGV travel:

http://www.fodors.com/community/europe/day-tripping-from-paris-468062-2.cfm

I'm assuming, however, that you are specifically interested in taking a TGV train somewhere for the experience and as was just mentioned you'll need to buy TGV tickets 3 months in advance to get the cheapest prices. Last minute purchase of TGV tickets will be expensive.

If you decide on this you'll need to use the TGV website to buy/reserve your tickets. For info on these trains use the website www.tgv-europe.com for schedules and prices. Don't forget to uncheck the box marked "Direct Trains" to see all possible options. If the TGV site redirects you to the RailEurope website then try again and enter Great Britain or Antarctic as your ticket collection country. Other countries may also work but just try to find a country that doesn't get you redirected to RailEurope. The RailEurope website often doesn't show all the trains and generally has higher prices but you can check just to compare. For trains that require reservations you can buy tickets up to 3 months or more in advance and the earlier you buy them the cheaper they will be. The discounted tickets are known as PREM tickets but these are non-refundable and can't be exchanged.

Here is a website that will tell you how to navigate the TGV website:

http://www.nickbooth.id.au/Tips/FrenchTrain.htm

BTW, what is the time limit you'd travel from Paris? Would you go further than 2 hours from Paris (which means over 4 hours round trip)? For example, most trains to Bruges take 2 hours 40 minutes and require a transfer in Brussels. The TGV will go to Brussels and from there it's a regular local train to Bruges. Do you mind spending 5 hours and 20 minutes of your day on a train?

Whit825: May be you find this link useful; I think it is great.
For our next trip to Paris; we are thinking of Reims, Chartres or Rouen.
Enjoy your return to Paris!
http://www.parisbestlodge.com/parisdaytrip.html

try the callanques at marseilles. Just fabulous. Or st tropez , antibes ...

Best places during the summer.

no hesitation.

While I love the Cote d'Azure (St. Tropez...honeymooned there)
isn't that a bit FAR for a day trip??

I think I'd try Epernay or Reims...and do a champangne tour. I'd have to have a driver tho <GRIN>

There are wonderful day trips without the TGV. Auvers sur Oise, Reims, Chartres, Rouen, the Loire.

Our best TGV daytrip from Paris was to Nancy, well under two hours by train. Nancy is a beautiful small city with an interesting history. It's an easy walk from the train station to the stunning Place Stanislas where you will find the helpful tourist office. Nearby is the Musée des Beaux Arts with its beautiful collection of art nouveau glassware. The Musée Lorrain is a short walk away, and the Musée de l'Ecole de Nancy with its important collection of art nouveau works is a short taxi ride or bus ride.

http://en.wikipedia.org/wiki/Nancy,_France