The minutes book contains the transcript made by the secretary of the City Council, of the content of the meetings of the Plenary. It shows the time when the session begins and the list of attendees, indicates who was involved and the issues addressed, the votes cast and the agreements reached. The minutes of each session, if agreed, are approved and signed by all those present at the next plenary meeting.

The minutes books of the Plenary Session of the City Council that are preserved in the Historical Archive of the City of Badalona cover the period from 1835 to 1945.