Six former employees of German arms manufacturer, Heckler & Koch, began their trial in Stuttgart on Tuesday. They are accused of illegally exporting of thousands of G36 assault rifles to Mexico.
Prosecutors say the export of 15 shipments of weapons between 2006 and 2009 breached both Germany's War Weapons Control Act and the Foreign Trade Act, because they ended up in especially violent parts of Mexico.
The defendants' lawyers instead claim the guns were legally transferred to a well-controlled police depot.
Human rights activists protested outside the Stuttgart court, holding banners reading "German weapons, German money murders all around the world." Protesters also repeated an accusation, shown on German broadcasters SWR and BR, that the G36 assault rifles were used in the notorious disappearance of 43 Mexican students in 2014.
The six defendants face up to five years in jail, while the Oberndorf-based company could be fined. The Stuttgart court has set 25 hearings due to finish in late October.