The inquiry, known as the Tibet Commission, interviewed over 70 people as part of its investigation into the events, publishing its findings on Monday.
The commission found the right of citizens to free expression was infringed in 2012 and 2013, during visits respectively by former Chinese president Hu Jintao and Yu Zhengsheng, the chairman of the Chinese People's Political Consultative Conference (CPPCC), a largely ceremonial political advisory body.
In addition, parliament was given inaccurate information regarding police action during the visits, the commission found.
A well as extensive interviews, the investigation also involved study of information submitted by the Independent Police Complaints Authority (Den Uafhængige Politiklagemyndighed).
“These are very serious findings,” Minister of Justice Søren Pape Poulsen said in a written response to the conclusions, reports Ritzau.
Protestors were prevented by police from making statements critical of China and were also prevented from being visible to the visiting Chinese president in 2012, the commission found.
Denmark's constitution, the European Convention on Human Rights and policing laws were disregarded in general orders given in relation to the visits, Ritzau reports.
Grounds for disciplinary action were found by the commission against Deputy Chief Superintendent Claus Hjelm Olsen, who was in charge of the police's handling of the visit, and Superintendent Henrik Oryé, who led three operations, the commission found.
Both officers were found to have given misleading information to parliament, while the latter also ordered a subordinate to give incorrect information, Ritzau writes.
The Foreign Ministry and police security service PET (Politiets Efterretningstjeneste) also received rebukes from the commission.
The ministry was found to have given information to police regarding the Chinese view of the demonstrations, without specifying any “agenda” for giving it.
PET passed information relating to Chinese concerns over the demonstrations to police. But the agency did not specify that this did not mean protestors must be kept from being visible to the Chinese officials, the commission found.