French is the national language and the Monegasque franc has the same value as the French franc. There has been a French-Monegasque customs union since 1865. There was a severe French-Monegasque crisis in 1962 for political and economical reasons. After 11 months of difficult discussions, a new fiscal status was adopted for Monaco. To have the same status, French citizens need to have settled in Monaco at least five years before the 13 October 1962.
Local taxes are also inexistant.
I found a large, recent picture of a Monegasque Carabinier about to hoist the State Flag above Saint Mary's tower in Monaco Castle. This was published in Paisajes , a complimentary magazine handed out to passengers in the Madrid-Seville high speed train, page 52, November or December 1999 issue. The picture is so large that even the folds in the flag are apparent, and measuring the flag's height and comparing it that of the Arms is straightforward. The collar surrounding the shield represents the Order of Saint Charles. The fringe appears to be one ninth of the height of the white field.