Finland's National Police Board says it is to investigate police actions at a demonstration on Saturday where an effigy of Turkish President Reccep Tayyip Erdogan was confiscated.
Police had taken the Erdogan effigy from protesters who were demonstrating in front of the Turkish embassy.
Police said they had interpreted the effigy as an attempt to discredit the Turkish president, and prevented that from happening.
Although the right to demonstrate in Finland is enshrined in the constitution, the law prohibits defamation.
In February demonstrators burned a picture of Erdogan in front of the embassy. Police have said they suspect that burning may have involved defamation of character.
"The investigation mechanism sets out a framework for legal actions by police in situations that leave room for interpretation," said Chief Inspector Henry Lehti from the Police Board.
Edited at 11:55 to add link.