It can very really from about €3,000 to about €5,000. Bear in mind that some electricians refuse to chase walls and so charge a cheaper price but a buiklder will have to be called to do this.
i hope the house is gutted as chasing the walls will destroy it
you could do the chasing yourself. its messy work but quite easy. all you need is a good mask (not paper) ,goggles and some battens nailed to the wall to keep the lines straight. aldi had wall chasers for 70-80 euro which are better than the hire ones as they are lighter, wont have blunt blades and are easier to handle. some stores still have them available eg athlone.