If your dog is lost, you need to make both a police report, and inform the chip registrars. This notification has to be made to the Microchipping Office at the Veterinary Regulation Directorate on 22925301 or firstname.lastname@example.org, and has to be done within 48 hours. They will then inform the sanctuaries and the animal welfare department.
All dogs 4 months and older must be microchipped, and at any age wear an ID tag on their collar/harness when in public. Either offence is punishable by a € 300 fine. You also significantly reduce the chances of getting your dog back if you don’t.