In case of a home repair, will the technician first inform me of the total cost?

When the technician visits, he will first examine with you what needs to be done to your bike. He will then give you a verbal estimate of the cost. If you agree, the technician will set to work.
So always make sure you know the cost of the repair in advance. You have the right to refuse the repair. In this case, you may be billed for the cost of the intervention, i.e. €59.