I think we discussed these briefly back in 2006, so this will hopefully be new to some members.

For much of the French colonial period in Louisiana (1682-1762), control over the province was exercised by a series of joint stock monopolies.  The most successful of these was the Compagnie d’Occident (Western Company), chartered by letters patent of Louis XIV in 1717, which also granted the company a coat of arms:  “an escutcheon Vert with a point wavy Argent, upon which a fleuve (river god) proper reclines against a cornucopia Or; a chief Azure semé-de-lis Or supported by a bar also Or; having two savages for supporters and a crown of trefoils.”

http://www.americanheraldry.org/pages/uploads/Roll/la-fr.gif

The company was expressly permitted to use these arms not only as a seal but also to place them on “buildings, vessels, guns and wherever it may think fit,” a right which the Western Company and succeeding governments of Louisiana exercised extensively.  In 1719, when the Western Company was subsumed into a new Compagnie des Indes, the royal letters patent stipulated that the new company would continue to use the arms granted in 1717.  Just 12 years later, in 1731, the French crown took direct control of Louisiana, but the arms of the company continued to be used as the arms of what was now the royal province of Louisiana.  For example, they were displayed above the door of the provincial administrative headquarters in New Orleans, embossed on artillery made for use by colonial militia,

The arms survived the transition to Spanish rule in 1762, subject only to the replacement of the French fleurs-de-lis in the chief by the quartered castle and lion of Castile and Leon in 1786.  In addition to being placed above the door of the Cabildo in New Orleans, they were emblazoned on the colors of the Louisiana Infantry Regiment raised by the Spanish in 1765.

http://www.americanheraldry.org/pages/uploads/Roll/la-sp.gif

Even after the United States took over Louisiana in 1803, the field of the old arms continued to serve as the basis for the New Orleans municipal seal.

http://upload.wikimedia.org/wikipedia/commons/a/a9/New_Orleans_City_Seal.gif