German police and customs officials raided over 50 exhibitors at the CeBIT technology trade fair in Hanover because of alleged patent infringements.
Over half of the exhibitors raided were from China or Taiwan.
Hanover police told reporters that they had filled 68 boxes with devices, documents, advertising material and gadgets in what they say is a crackdown on patent infringement.
CeBIT is a major annual technology trade fair in Hanover at which manufacturers display and unveil their latest products to the industry.
Associated Press quoted German police as saying that: "the background is the number that has been rising for years of criminal complaints by the holders of patent rights in the run-up to CeBIT".
The police and customs officials raided 51 stands, saying that 24 of the exhibiting companies were from mainland China, 12 were from Taiwan, nine from Germany, three from Hong Kong and one from each of Korea, the Netherlands and Poland.
Police said that they had been alerted to potential patent violations by patent holders, who had "pointed out to the affected exhibiting firms in good time the lack of licensing contracts", according to AP.
Police did not identify any of the companies involved but said that devices seized included MP3 players, MP4 players, digital video players and blank CDs and DVDs.