local car rental

I have been using for many years the service of this company in Germany, for car rentals around the globe, so far without any problem.

http://www.billiger-mietwagen.de

The system which has good rating from comsumer associations automatically compares offers from a range of companies and has access to prviliged rates of the big car rental providers. You may well end up get a Hertz or Avis or Sixt car... 

An addivional advantage is that you can get full insurance at a privileged rate as well given that this provider has a framework contract to which you get access if you take the full insurance option

Works in Brussels as well.