Can my neighbour start his car and let it run idle in the morning?

No, it is forbidden to let the engine run idle without necessity, as it is forbidden to start motorbikes our bikes with an auxiliary engine in the entrance area of buildings, passages or courtyards of residential buildings. During the night the noise caused by the closing of car doors et garage doors, as the starting or stopping of car engines should not disturb others. (Art. 27 General police rules of the 26th of March 2001 as modified on the 23rd of November 2015)