In 1997 - 13 smaller and medium size holiday agencies founded the Association of German Holiday House Agencies (Verband Deutscher Ferienhausagenturen, abr. VDFA). They associated with the intention of distinguishing themselves from dubious suppliers. By now some 50 agencies are co-operating within the VDFA.
As Helmut Scheel, founding member and former president, underlines:

What do we offer:
We offer to book a holiday house, also through internet, at comparable prices. We maintain our promises, individual help and advice is our motto. We do care for the interest of our holiday guests – it is important for us your holidays turn out to be a success for you, as in the end this will be our success as well and you will recommend us to others. Travel with VDFA perhaps not the whole world but a part of it using the services of small and medium size agencies where people still personally know the properties they offer.