Foil-wrapped chocolate coins flew onto the field in the Bundesliga on Friday as fans made their unhappiness with an investment deal clear by forcing the action to be briefly stopped in Borussia Monchengladbach's game against Werder Bremen.

Fan groups across Germany have pledged to protest the league's plan to sell a stake of future broadcast revenues to an outside investor. The groups have agreed on a silent protest with no singing and chanting for the first 12 minutes of each game this weekend.

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When the 12 minutes were up, Gladbach's fans went a step further by hurling the chocolate coins in gold foil -- a common holiday gift for children -- onto the field. There was a five-minute stoppage while stadium staff, joined by referee Felix Zwayer, picked up the coins.

There were also protests in the second division. A game between Paderborn and Hansa Rostock was briefly stopped because Rostock fans followed the 12 minutes of silence with a display of flares.

"We are not prepared to stand idly by as German soccer gets sold out," the groups said in a joint statement.

Fans have been protesting with banners at Bundesliga games for months and fear an investor could pressure the league to change how the competition is run and focus more on TV viewers than the fans in the stadiums.

The fan groups say their "biggest weapon" is the way that the Bundesliga's marketing focuses heavily on Germany's packed stadiums and passionate crowds. Past protests played a key role in the league abolishing unpopular Monday evening kickoffs in what was widely seen as a victory over broadcasters.