Postage stamp collecting

Ein Portal zur Aerophilatelie in Deutschland
Website in German devoted to German topical stamps, specifically aerophilately

Philatelie Alexander
Site in German of the philatelist Dirk Alexander, with an interest in German topical stamps

Bundesarbeitsgemeinschaft Münzen und Geldwesen
Site in German of an organization interested in coins and monetary systems, they have a section of their site displaying German topical stamps with the Euro as a theme

Thompson, William - William's Stamp Page
Interested in German stamps, has a separate section for German topical stamps and German inflation stamps issued from 1919 to 1923

Internationale Motivgruppe Eisenbahnwesen
An organization founded in Germany with a special interest in train and railway-themed German topical stamps

Polizeiphilatelie
Site in German devoted to German topical stamps related to police organisations

Argesh
Site in German devoted to German topical stamps particularly Schlesvig-Holstein, Hamburg and Lubeck.

Stampwolf
A stamp dealer of German topical stamps, namely World War 2 German propaganda stamp forgeries