Planning a Christmas-market weekend for three people. Initial thought was Zürich or Sélestat / Alsace; on discussion, Colmar is probably the Alsace destination John had in mind. Current preference is a weekend rather than a longer multi-city trip.
Colmar is the strongest candidate for a short Christmas-market weekend: compact, very picturesque, and with several market areas spread through the historic centre rather than one single market. It should work well for two nights without needing to spend much of the weekend travelling between places.
Likely shape: travel out on Friday, stay Friday and Saturday nights in Colmar, spend Saturday exploring the markets and old town, then have some more time in Colmar on Sunday before returning home.
Possible extra excursion only if it feels worthwhile rather than compulsory: Eguisheim or Riquewihr. For a two-night weekend, avoid trying to combine Colmar, Strasbourg, Basel and Zürich unless transport timings make it unusually easy.
A practical route to investigate is Bristol → Basel by air, then train from Basel to Colmar. This keeps the destination itself compact and avoids hiring a car. Exact 2026 flights, fares and train timings still need checking before booking.
Strasbourg is the alternative if the priority shifts towards a larger city, more restaurants and nightlife, and a bigger Christmas-market experience. Colmar currently seems a better fit for a picturesque two-night weekend.
Zürich remains an option if the main aim becomes Switzerland rather than Alsace. For a weekend focused specifically on Christmas markets, Colmar currently looks more appealing and better suited to a short stay. Basel could also be considered as a Swiss alternative because of its own Christmas market and its position on the route towards Alsace.