i hope you understand some English?
the 'bouton' under the light switch is the 'coming home/leaving' home function.
when you press the switch it will light up, when you leave you car by darkness the outhside lights will light up for a few minutes.
when you open your car with the remote key when it is dark the lights will turn on again..
(the time/minutes that the lights will keep on shining can be installed by the dealer, from about 5 seconds up to 1 minute)
you other question i don't understand becaus my French is not that good..
contact the import dealer of your country (belgium = D'Ieteren) and ask for a French manual, not shure if they will sent you one, but shurely you can get one at the local Audi dealer (but he will not be happy as you bought the car in Germany )
have a nice time with the car!