Switzerland

For most countries, including France, A Eurail pass is usually more expensive than advance purchase tickets.
For more info see here: http://www.seat61.com/Railpass-and-Eurail-pass-guide.htm#railpass-or-point-to-point-tickets

For Switzerland, a Swiss pass, or a half fare card may be cheaper than individual tickets, especially if you are taking a lot of local trains in the mountains. You need to scope out your trip and do the arithmetic yourself

The price comparison between a Swiss Travel Pass, a Select Pass covering both countries, and a mix of point-to-point tickets depends entirely on your destinations and number of travel days needed. A 2-country Select pass can actually start out cheaper for the same number of days, but there will be other expenses that necessitate you making a comparison chart. A 15-year-old is free with parents when buying a Swiss Travel Pass or Half-Fare Card, but not with a 2-country pass or French train tickets. Discounted rides are only on counted travel days with a Swiss pass, but lesser discounts are available without using a counted day on a 2-country pass. Read carefully through the differences in Swiss coverage and the French seat reservation fees. If "doing France" means only one or two train rides, then you probably could reserve advance-discount tickets for those.

Thank you.