Hello

a recent change for Berdorf

http://www.environnement.public.lu/guichet_virtuel/Escalade_Klettern/

No need to request a permit anymore :-)

However you must be affilitated to a "fédération internationale d´escalade (UIAA et IFSC)" i.e. a internationnal climbing federation

Looking at wikipedia

https://en.wikipedia.org/wiki/International_Federation_of_Sport_Cli...

BMC, NKVB, DAV, Belgium Alpine Club are OK

However French Alpine Club (CAF) doesn't work for example - you should join the FFME which is a different organisation

Better is to check with your own alpine club

Bruno