After defying compliance with the cease and desist requests on December 6, asking them to stop selling HTC's 3G handsets by Dec. 20 German retailers have been sued by patent firm IPCom for patent infringement for continuing to sell phones made by HTC, the No. 4 smartphone maker globally. 

According  to media reports a court in Mannheim, Germany, ruled in February 2009 against HTC in a patent fight with IPCom, allowing an injunction against sales of HTC phones using UMTS technology and setting a penalty of up to 250,000 euros ($326,000) each time the injunction was violated. 

All HTC smartphones use UMTS technology. After HTC dropped an appeal of the ruling, a court in Karlsruhe, Germany, in late November said the injunction against HTC smartphone sales in Germany could be enforced. 

IPCom said in a statement on Thursday that it sent 100 retailers cease and desist requests on December 6, asking them to stop selling HTC's 3G handsets by Dec. 20. 

"Since this deadline has passed without any of the retailers complying, IPCom has sued them for infringement of patent #100A themselves," IPCom said, adding so far it has sued around 30 retailers.