These records are manuscript letters addressed to the Conseil de Ville by the Mayor over his signature. These communications served more or less as official messages to the Council, although there does not appear to be any statutory basis for the practice. The messages contain a wealth of sometimes detailed information on the problems facing the city and the manner in which those problems were addressed. Typically, the Mayor would notify the Council of the existence of a problem requiring attention, possibly suggesting a solution of his own. Also included are notices of the Mayor's approval or disapproval of Council ordinances and resolutions. In some instances communications addressed to the Mayor, or copies of such communications, were included for the information of the Council. A reading of the proceedings of prior and/or subsequent Council meetings along with the individual letters should provide a fuller understanding of the processes at work. These messages may also be transcribed in the proceedings of the Conseil de Ville and may also be included with the published proceedings of Conseil de Ville meetings in the newspapers and elsewhere.

The original messages were recorded in French; English translations are available. The WPA translations also include tables of contents compiled by the translators to indicate the topics covered in each of the messages.