West Ham reluctantly sold the Austria striker to Shanghai SIPG this week for €25m.
DeichStube says Werder will be due a percentage of the fee thanks to training rights.
Five percent of the transfer fee goes to the clubs that have trained the player between the 12th and 23rd birthdays. That corresponds to 0.5 percent per year. Because Arnautovic was active in this period for two years with Werder, it will be one percent due.
Based on €25m transfer fee, the amount going to Bremen will be €250,000.