Here in New Mexico we have to run UF in the adobe walls, real pain in the caboose.
Well, welcome to Continental European wiring!
The only difference being, most of our buildings (except for some rural farm houses) are rock solid brick instead of adobe, including all interior walls.
You either need a slot cutter (basically an angle grinder with two parallel blades and dust collector) and chip out what's left between the two cuts (very common in Germany) or a rotary hammer drill with a flat chisel bit (most common in Austria, less dusty and less likely to hit live old wiring). In the old days they did everything with a cold chisel and sledge hammer (usually 4lbs.), for smaller jobs that's still used.
On my summer job we channeled rock solid brick walls for 2 1/2" conduit with hand tools. Go figure...