Police said that Klaus Rösler was hit with a plastic bag full of jam but remained uninjured.
They were unable to say what flavour of jam had been in the bag - although it looks like a red berry.
Rösler had been on the way to a meeting at the Schwarzkopf Foundation in central Berlin.
The organization tries to get young people involved in European politics.
But he was hit by the sticky projectile while passing in front of a group of 50 demonstrators protesting against the EU's refugee policy outside the building.
Police were able to prevent members of the group from entering the meeting hall later in the evening.
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Around 150 people conducted a peaceful demonstration outside without further incident.
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