There are associations, often national based, which run accreditation schemes : schools have to meet certain quality standards - both in terms of the service they offer their students (facilities, staff qualifications, welfare services etc) and the conditions of employment of their teachers. In Italy the relevant organisation is known as
AISLI, in Britain there's
Accreditation UK in partnership - a partnership of three organisations including the British Council. Have a look at their website to see the sort of standards they require.