I found it. The book is Cauchemar à louer, translated to Romanian as Coşmar de închiriat (which translates toin English, Nightmare For Rent) by Serge Brussolo.
THE HOUSE ON THE HILL...
A grey, gloomy fortress, with open windows like unhealed wounds.THE TOWN...
A fortress protected by bars, a strange zoo, attacked by ferocious and merciless visitors.THE FOREST...
An infernal hatisthicket, full of rusty traps, fatal a century ago, still fatal today.The rented house is the secret gate to another world, which grows like a tumor in the flesh of reality, transforming places and people into something terrible and foreign.
For David and his parents, the house on the hill is a...
NIGHTMARE FOR RENT..