The protests came as Polish President Andrzej Duda has tested positive for coronavirus, authorities said on Saturday (October 24).
Duda's infection was announced in the morning and he said in televised remarks later he was feeling fine.
Poland is seeing a sharp rise in COVID-19 cases, with new infections hitting a daily record of 13,632 on Friday. New restrictions went into force on Saturday.
Protesters gathered without face masks, saying curbs are not needed and holding up banners saying "Let us work, and let us decide on our own".
Police responded with force, including tear gas, on several occasions. Protests are banned in light of the pandemic, Warsaw police spokesman Sylwester Marczak said, adding some in the crowd were aggressive at times.