The Saarlouis thing is a screening of suitable candidates by an independant company for Cargolux. I did it in 2002. Cargolux pay for the hotel, but not transport.
The screening takes a day and consists of a medical, aptitude and psycometric tests followed by an interview with a shrink. The medical is standard, except none of the nurses spoke english so I had to rely on my poor German. The aptitude tests were again standard - I had most of them all before including some which the RAF had binned as being useless. I know - as I was involved in the descision to stop using them! The psycometric tests were poorly translated into English from German and were written for young people who were applying for ab-initio training so some of the questions were not applicable to those who were already pilots. But you still have to answer them! The interview was about 20 minutes long and more like a job interview, but I'm sure the shrink got enough background info for his report.
Not very impressive IMHO - and I don't think Cargolux are being served properly by IBF.
PS. I didn't pass and don't know why. However, I was offered a job with Cargolux through PARC so the failure didn't matter. I didn't accept the contract when I saw a Cargolux roster!