Nine people were detained at a pro-Palestinian rally and demonstration in Frankfurt on Friday, according to the police.
Police are investigating those detained on suspicion of crimes including incitement to hatred and the use of unconstitutional symbols, they said in the evening.
Around 850 people took part in the demonstration in Frankfurt city centre that was held under the banner, “Ceasefire in Gaza.”
Police said they seized a sign with what they described as “SS runes” and arrested the woman carrying it.
Another woman held up a poster depicting the flag of the state of Israel in a rubbish bin – and the words “Keep the world clean.”
The officers also seized that sign and charged the woman with suspected incitement to hatred.