The Anthem of French Guiana
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The addition of the adjective "French" comes from colonial times when three such colonies existed: British Guiana (now Guyana), Dutch Guiana (now Suriname) and French Guiana. The three are still often collectively referred to as the Guianas.
Like all departments of France, whether within metropolitan France or overseas (like French Guiana, located in South America), "La Marseillaise" is used as the national anthem. (Unlike other nations with second-level administrative areas, French departments are less likely to adopt unofficial regional anthems.)
Above is a maximum card with the anthem composer, Rouget de Lisle, issued in 1936.