De Coussemaker came into contact with the intellectuals of Europe, especially with the German cultural world; the brothers Grimm and Baron Kervyn de Lettenhove for instance. Honoured in the "Légion d'honneur" in April 1847, titleholder of the "Ordre de Saint-Grégoire le Grand", member of more than 25 academic societies, he was a member of the "Académie royale de Belgique" ("Royal Academy of Belgium"), correspondent for the "Institut de France", and correspondent for the "Académie des Inscriptions et des Belles-Lettres". His impressive library included 1600 valuable books and numerous musical instruments, part of which came into the possession of the Royal Library of Belgium in Brussels ("Koninklijke Bibliotheek van België").