Greetings and salutations

You have 7 days of potential travel, starting from Paris.

1st of all, I’lld recommend you to keep to a logic, geographical route. Now you start going north, than quite far east, before slowly returning south-west. There’s no logic in that. You’ll spend too much time on trains, you won’t effectively enjoy visiting places.

I note you want to visit a christmas market, and perhaps venture through the Alps. Germany is quite well known for its Christmas markets (Weihnachtsmarkt). Basically every town or city has one in the period you’re travelling.

So I’lld start by going east, take trains from Paris Gare de l’Est towards Germany. Interesting towns and cities to stop over are Strasbourg (Fr), Colmar (Fr), Freiburg (im Breisgau) (De), Stuttgart,… It can be nice to stay in a smaller town or village in the Black Forest if you like a bit of nature. Daytime light is limited, so you might want to pick a bit of a bigger city as hide-out to have some entertainment in the evening. I wouldn’t go any further east than Munich.

Being there it’s quite easy to get to Switzerland from there (East of France, South-West Germany).

Note that reservations in Germany are optional, and non-existent in domestic Swiss trains. It can be nice to just cruise around Switzerland by train, sticking to the Alps and enjoying the views. But again, daylight is kinda limited this time of year. Other community members gladly recommend scenic Swiss train routes.

I wouldn’t go directly south, to Italy. French-Italian cross border trains are not optimal and you can lose a lot of time doing that.

From Genève in Switzerland you can get easily back to France. Nice cities you might want to discover that kinda lay on your route are Lyon, Grenoble, Avignon, Nîmes, Montpellier, Carcassonne, Toulouse… Again, I wouldn’t continue east, further than Marseille nor go back north from there.

From there you can get to Spain. Possibly via local trains at Cerbère Portbou, there’s a suboptimal high speed train connection that sells out very early for pass holders.

Spain itself I don’t know that well, but also dozens of options to visit. Other community members can come up with better suggestions than me. The climate in the south of France and Spain will be quite pleasant in comparison to temperatures North of the Alps.

For reservations, I can guide you to this link with reservation overview for all of Europe

Spain and France are considered “harder” countries for reservations. At least reservations there are more expensive than in the rest of Europe. In Spain you can only get reservations at the counters in the stations.

Basically you can do everything on my suggestions, via slower, reservation free regional trains (mainly in France and Spain). In Germany reservations are only optional.

General recommendation. Don’t rely on the rail planner app for itineraries and route scheduling, but use the national apps and planners. (You’ll be taking SNCF, Deutsche Bahn, SBB-CFF-FFS, and RENFE.) Deutsche Bahn has a good international rail planner, guess you’ll find the most information there.

For cheap0 flites-also even direct to SVL-but often many more to nearby Malaga: ryanair and wizzair and also others like vueling. These are all low-cost budget airls, Ryan is extremely cheap and also extremely nasty if you do not very strictly follow their rules-esp re luggage etc. Do not expect any mercy if you fail in that-US style screaming ´scam´ will not work for that. Most also do ´black friday´sales coming days.

Brendan has already written exactly what I had in mind.

Oh-and frankly-these Weihnachtsmärkte=Xmas fairs tend to look very, very much the same like Oreo cookies everywhere, only the size varies a bit with size of town. MOst are also much aimed at getting drunk asap by ´glühwein=mulled heated wine+ some spices.

Except for the trains in FR and ES you do not need any RES for daytime in Germany-CZ-Austria, but can do if the nerves are too bad for you.

Consider a one way journey - look for a low cost flight from your local airport and use that as your start point then work your way back home using your pass for the big jumps. 

For example a flight to Germany (e,g, Cologne or Munich) for a couple of days, then a trip through the alps (Munich to Milan (Travel Day 1). Then onto Nice/Monaco via Ventimiglia (Travel day 2), then to Marseilles to Cerberes to Barcelona (Travel day 3) then home via Madrid and Seville (Travel day 4).  Obviously you could do Germany - Brussels - Paris - Barcelona - Seville.

But don’t try to visit all these for one night and onwards.  On a seven night break I would suggest two or maybe 3 hotel stops.

One other point - Travel days can also be used for day trips, so,for example, if you base yourself in Frankfurt you could day trip using your pass to Cologne, Stuttgart, Munich etc, or base in Vienna and trips to Budapest, Graz, Bratislava, into the alps and so on. In Germany for example their high speed ICE network is extensive and no reservations needed so a radius of 150 - 200 km is realistic for 1 - 1,5 hrs there, several hours touring and back in a day.