Cool places to overnight between Rotterdam and Freiburg?

[biggles330d]

So, we're at a music festival in Rotterdam in July and heading to Freiburg in Germany afterwards. We've a night to book between them and are looking for somewhere cool or interesting to stop. Spa could be an option, or anywhere in Lux, Germany or France between the two - I'm relaxed about the route or going a little bit out of the way. It's not the usual route through Europe so I'm not familiar with whats worth going via.
We'd rather not stop at boring corporate hotel or Ibis, but find something a bit different, interesting or near somewhere worth exploring.

Any experience or suggestions??

[RC1807]

Just checking your actual destination as Freiburg is kind of NE of Rotterdam, so I was confused as to why you’d mention Luxembourg as being en route.

I suspect you’re referring to Freiburg im Breisgau, between Strasbourg (F) and Basel (CH)?