Paris to Swtizerland

I believe the high speed train Paris to Lausanne is fastest and right on Lake Geneva. Check the train schedules, maybe to Geneva also would be fast.

By "day trip" do you mean returning the same evening after dinner? Book these TGV trains in advance for the best prices.

This early departure ends at Lausanne, on the lake. You can do a shorter lake boat while there. Evian would require a longer train ride.

Paris Gare de Lyon 07:57

Dijon Ville 09:28 09:31

Dole Ville 09:56 09:59

Frasne 10:40 10:42

Vallorbe 10:57

Lausanne 11:37

The last return trains to Paris depart Lausanne at 18:20 or Geneve at 19:40.

I wouldn't suggest using a train / boat combination, as that will take longer than by rail alone. The quickest trip will be Paris to Geneva at about three hours each way. If you want to have dinner overlooking Lake Geneva in another location such as Lausanne or Montreux, travel time will be longer. Do you have a preference for which place you'd prefer to have dinner?

Using a direct train rather than one with changes will be easier. That will be a long travel day for a short dinner!

I really have no preference. Just want something nice to celebrate my wife's 30 birthday

In France dinner service starts at 7 or 7:30 pm. French speaking Switzerland would be similar. That's also the time the last train for Paris leaves, according to Laura.

You're in Paris already. I can think of a lot of more wonderful things to treat my wife to than riding a train for 6 hours to have a meal almost as good as one you could Paris at twice the price.
Or do you live in Paris and find yourself jaded?

Have to agree with Sam that riding a train all the way to Switzerland for a few hours, particularly when you are already in Paris, would be low on my list. In fact, Laura's early departure was nearly four hours one-way. Have you considered the Michelin starred restaurants in the Bois de Boulogne in Paris?

James,
Full train timetable Paris to Switzerland is here: http://www.tgv-lyria.com/sites/default/files/pdf/BROCHURES_CO/TIMETABLE-2016S2-ch_fr-TGV-LYRIA-EN_0.pdf
For Paris to Geneva see page 2. First train out of Paris (07:07) will get you to Geneva 10:16. Last departure from Geneva is 19:42.
This is really too far for a day trip. As others say, you will not get dinner overlooking Lake Geneva as you need to be back at the station before 19:42. And Switzerland is not just Geneva, you really need to see the Alps, which are another 1-2 hours past Geneva.
I recommend a (minimum) 3 day trip staying somewhere in the Berner Oberland, with a call at Geneva either on the way there or back.

To get the cheap fares you need to book this 60+ days in advance on http://www.tgv-lyria.com

P.S. If you want a birthday day trip from Paris, try London. 2h20 from Paris Gare du Nord to London St Pancras. Many more trains (full timetable here: http://www.eurostar.com/sites/default/files/pdf/timetable/6551%20UK%20issue%2077.pdf ). 1 hour time difference is in your favour (first train from Paris 06:43, arrives London 08:02 UK time), last departure from London 20:01.
Many companies do day trips where a guided bus tour is included. Try Googling: Paris to London day trip
Or you can book direct with the train operator, again book early for cheap fares here: http://www.eurostar.com

james,

Are you limited in terms of the place you want to celebrate the birthday? Do you have a "generous" budget for this trip?

Although it would mean a lot of travel time for a short trip, one possibility would be.....

• travel by high speed TGV from Paris Gare de Lyon to Lausanne (departure at 07:57, 3H:40M, direct)
• spend a few hours sightseeing in Lausanne, perhaps with a boat trip on the lake.
• reserve dinner at one of the better local restaurants such as Michelin Château d’Ouchy which is close to the lake.
• since it likely won't be possible to return to Paris the same day also arrange a room in a hotel, such as the one mentioned above.
• arrange for a room service breakfast the following morning to add to the celebration.
• check-out of the hotel at about 11:30 and make your way back to the station in time for a 12;23 departure back to Paris.

While it's a longer trip, it is possible.

A train ride of several hours, each way, just to eat dinner would not be my idea of a birthday treat, but you know your wife better than we do.

If you're looking for something special involving a view, perhaps a dinner cruise on the Seine? Here's a thread comparing the options; the more upscale ones cook the food on board, the others merely reheat it. For what you'd spend on dinner in Geneva (not to mention the train fare), you can splurge for the Yachts of Paris.

https://community.ricksteves.com/travel-forum/france/seine-dinner-cruise-dc22bdbb-209a-4e9d-ad14-75ed3893bdde

With 2 days perhaps ...

Day 1
TGV 9761
Dep 07:07 PARIS GARE DE LYON (France)
Arr 10:16 GENEVE (Switzerland)
... then on to Laussanne for overnight

Day 2
Morning to Bern, then on to Basel
TGV 9230
Dep 18:34 BASEL SBB (Switzerland)
Arr 21:38 PARIS GARE DE LYON (France)