They raised slogans against the Act and wanted its withdrawal, police said.
Placards like 'Advocate Amendment rule is Draconian rule' and 'injustice to advocates is injustice to common man,' under the banner of Coimbatore Bar Association, they said.
A large number of police personnel were deployed in and around the venue of demonstration.
The Madras high court had recently issued a notification making amendments to existing rules under the Act with a view to ensure peaceful conduct of court proceedings and suggesting disciplinary action to be taken against erring advocates.