Protest leader Parit "Penguin" Chiwarak reported to Samran Rat police on Wednesday to answer a police charge of damaging public property during a rally at the Democracy Monument on Oct 14.
He was accompanied by Noraseth Nanongtoom of the Thai Lawyers for Human Rights Centre.
Mr Parit said he reported in response to a police summons and was charged with causing damage to public property during the rally.
He said he and other demonstrators had merely moved potted trees from the base of the monument to a space nearby and had not seen any damage to either the plants or pots, so he thought the lawsuit was merely intended to keep him distracted.
Anti-government movement leaders, including Mr Parit, have been summonsed to hear multiple charges, one after another, in connection with demonstrations at which they have demanded the resignation of Prime Minister Prayut Chan-o-cha, the rewriting of the constitution and reform of the monarchy.
The most serious of these have been charges related to the lese majeste law, under Section 112 of the Criminal Code, which carry hefty prison terms.
Meanwhile, actress Inthira Charoenpura -- also known by her nickname Sai -- yesterday posted a picture to her Facebook page of a warrant relating to the lese majeste law.
In the warrant, Bang Khen police asked Ms Inthira to meet investigators on Dec 21. She gave no further details in the post.
The Criminal Court yesterday acquitted Pansak Srithep, a core member of Resistant Citizen, an anti-junta activist group, over his participation in a political rally involving a group of more than five people on March 15, 2015.
The protesters walked from the Department of Science Service in Ratchathewi district to Thammasat University to protest against the-then National Council for Peace and Order.