In reply to Legs:
I also found myself in Bordeaux for a nearby wedding. Third the St Emilion suggestion.
The toruist office in the centre of the city is really good - one of the best I’ve found. They can organise days, book hotels etc. They booked me a day of wine tasting with a cooking course, at a nearby chateaux, all at the last minute.
Visit the law courts if you’re interested in modern architecture
Musée des Beaux Arts is world class if you’re into art
St Jean de Luz is a beautiful seaside town you can reach by direct train. Very French but culturally quite different to most of the country