I'm going to Luxembourg by car and I'm looking for a place where I can park for free. It should be also close to the city center - a maximum of 20 minutes walking distance from the old town.
There are 5 so-called P+R's (= Park and Ride) around Luxembourg City.
All but one are totally free. The one at Bouillon is only free for the 24 first hours. When you arrive from Germany, Kirchberg is conveniently located. Otherwise, go to Luxembourg-Sud. It is next to the junction of the highways from Germany, France and Belgium. Kockelscheuer is a bit more remote, but still okay. Beggen is not practical if you arrive from abroad.
Each of these parkings has good and frequent bus connection to the center of Luxembourg City. You can reach the city center in less than 20 minutes from each of them.
There is strictly no free parking space within 20 minutes walking distance from the city center. As a matter of principle, in Luxembourg City, all the parkings except the P+R have to be paid for.
If you can read some French, have a look athe the following official links