We strongly advise to adopt a dog from a shelter rather than buying one. In some countries healthy animals can be still be legally killed after some days if they are not adopted, so your decision to adopt can literally save a life.
Below you find the links to national websites that list public and private shelters you can contact to adopt a dog.
List of shelters: http://lachistance.be (the website indicates if the shelter is killing healthy animals or not)
List of "official" public shelters: http://www.30millionsdamis.fr/jagis/jadopte-un-animal/
List of rescue organisations that offer dogs for adoption: http://www.secondechance.org/refuge/list?espece%5B%5D=1&Region=&Departement=&commit=Rechercher+%21
List of public and private shelters (arranged by species): http://www.tierheim-deutschland.de/
List of public and private shelters: http://www.prontofido.net/index.asp?action=05
List of public and private shelters: List of Romanian Shelters