At the very heart of the coat of arms of the City of Paris is a nef (a large ship from the late Middle Ages). But why use such a symbol to represent a city almost 200 km from the sea?

The nef symbol in the coat of arms of Paris is actually descended from the "Hanse des Marchands de l'Eau" ("Hanse of the Water Merchants"), a brotherhood of merchant sailors who managed business on the Seine and developed trade between the city and the rest of the world. They used a nef as their seal. The symbol can even be traced back to the Nautes of Lutetia (a brotherhood of Gallic shipowners from the Parisii tribe) in Gallo-Roman times.

It was Philippe Auguste, who left for the third Crusade to the Holy Land (the region in which Jesus Christ lived, particularly Jerusalem) in 1190, who gave the City of Paris its first coat of arms:
"a shield whose field was gules, a nave argent, a chief azure, sown with golden fleurs-de-lys".

The ecu would have found its red background in the banner of Saint Denis, which symbolises the blood of martyrs in times of war, while the nef and the waves obviously represent the Hanse des Marchands de l'Eau corporation, which had enjoyed the privilege of the right of navigation on the Seine (from Mantes to Paris) since 1170. The blue band is thought to have come either from Philippe Auguste, who wanted it to represent the rare colour worn by the Virgin Mary, or from Charles V, who chose it to represent the supremacy of royalty over the City of Paris, which would explain the golden fleurs-de-lys that dot the seal.

The first person to officially recognise the seal of Paris was Louis IX, known as Saint Louis. From then on, it was used to seal deeds issued by the Provost of the Merchants, an official who headed the Hanse des Marchands de l'Eau and who, assisted by four aldermen, was elected every two years to serve as Mayor of Paris (or the equivalent under the Old Regime).

In November 1790, at the height of the Revolution, the municipality of Paris abolished its coat of arms following the abolition of the nobility. The city's coat of arms was changed under the First Empire, with three golden bees replacing the fleurs-de-lys, the goddess Isis at the bow of the nef and a silver star above.

The traditional coat of arms was reinstated during the Restoration, by letters patent from Louis XVIII in 1817, but the Second Republic then replaced the fleurs-de-lys with stars, before the advent of the Second Empire and Napoleon III allowed the original motif to be restored.

Nowadays, Paris coats of arms are decorated with a number of symbolic external ornaments that have been added over time:

Two ornaments, an oak branch to the right of the shield and a laurel branch to its left. A stamp, surmounting the shield and ornaments of a five-tower mural crown. The city's motto, "Fluctuat nec mergitur", which can be seen below the shield and which overlooks three Orders: the Cross of the Legion of Honour, the Cross of the First World War and the Cross of the Liberation.

Fluctuat nec mergitur, the latin motto of Paris which means "It is beaten by the waves, but does not sink", accompanies the symbol of the nave and appears for the first time on a token from 1581. At the time, it was slightly different from the current version, which appeared in 1582: Fluctuat at nunquam mergitur, which literally means "Beaten by winds that push it in opposite directions, it is held back on the waves by a hand from heaven".

However, the motto was not officially adopted by the city until after the Revolution, following a decree issued on 24 November 1853 by Baron Haussmann, then Prefect of the Seine.

The three Orders that appear at the bottom of the coat of arms are the most recent additions, since the Cross of the Legion of Honour was added following the decree of 9 October 1900. The Cross of War from 1914-1918 followed the decree of 28 July 1919 and the Cross of the Liberation followed the decree of 24 March 1945.