If you are traveling to either France or Switzerland this fall, you can include an affordable side trip to the other country with a First Class France-Switzerland Deluxe Pass from Rail Europe.

The pass costs $399 for a limited time and allows six days of first class train travel in the two countries over a period of one month. You can travel on both the French and Swiss rail networks, as well as the high-speed TGV Lyria train that connects the two. So, is it worth it?

We did some research to gauge just how much the pass could save you, and our verdict is, yes, the pass is worth the money – if you plan to do a lot of traveling.

Take, for example, an itinerary that involves flying in and out of Paris and adding a trip to two Swiss cities and one other French city. Without the pass, train travel from Paris - Bordeaux - Geneva - Zurich - Paris would cost $915 in first class (or $514 in economy). Compare that to $399 for first class travel with the pass. We also love that, unlike many rail passes, travel does not need to be on consecutive days, giving you time to enjoy each city, rather than rushing through. The only catch is that you still need to pay an additional reservation fee to travel on the Lyria (and on the above itinerary, you would pay it twice), although the fee can be as low as $43, so you'd still save.

The savings are pretty big if you were planning to travel first class anyway; marginal is you would have been happy in economy.

A note on first class trains in France and Switzerland: All travel classes on these trains are generally better than we're used to in the United States. But French and Swiss first class has the additional bonus of large reclining seats with generous legroom, quiet cars, and, when available, "solo seats" that are situated on their own next to a window and have a table.

Here's how the deal breaks down: The new Deluxe Pass is actually made up of two passes: one France Rail Pass (valid for three days of travel in France within one month) and a Swiss Rail Pass (valid for three days of travel within Switzerland in one month). For cross-border travel on the TGV Lyria, you will need to use at least one travel day from either your French or Swiss pass – if purchasing the cheapest reservation, you'll use one travel day from each pass.

You can purchase the mandatory Lyria reservations at three different 'tiers,' depending on how you'd like to arrange your trip. The prices vary depending on the route (i.e. Paris-Zurich vs. Paris-Geneva). The following fares, as an example, are based on Zurich to Paris. Tier 1 costs $43 per person, can only be in first class, and requires a travel day to be used on both the France Rail Pass and the Swiss Pass. A Tier 2 reservation costs $145 per person, also must be in first class, and requires a travel day to be used on the France Rail Pass. A Tier 3 reservation costs $229 per person in first class and $140 per person in second class, and requires that a travel day be used from the Swiss Pass. So, if you wanted to user up fewer travel days on the pass, you might need to pay for the higher tier reservation, but if you want to follow an itinerary like the one we posted above, a Tier 1 reservation for $43 works just fine.

Even with all these slightly complicated restrictions, the pass is still a good deal if you want to visit several cities. The itinerary we mentioned above would cost less than $500, including the cost of the pass and two Tier 1 reservations for the Lyria; would use up exactly six of the six allowable days, and include visits to four different cities. If, on the other hand, you only want to make one round-trip journey (say, Paris to Zurich and back), an economy class ticket would definitely cost less than $399.

You can book the First Class France-Switzerland Deluxe Pass until October 16, 2013 and can use it for up to six months after purchasing. In addition to the travel savings, you can show your Deluxe Pass for more perks in the two countries, including free entrance to over 400 museums, as well as discounts on mountain railways, cable cars and city passes in Switzerland, and discounts on castles, shows, attractions, museums and city passes in France.

Note: Residents of Europe are not eligible to purchase the pass.