This is my bicycle trip that covered 3 countries within 3 hours. See the track in Sportstracker.
I wanted to start at Wormeldange, small town close to river Mosel, but couldn't find parking. Across the bridge, on the German side, there is spacious "Mitfahrerparkplatz" of Wincheringen. First I pedalled on the German side of the river to south, towards France. In France I crossed the river and rode back on the Luxembourgish side.
This is Wormeldange