Giffard Orange Curacao is made with a combination of bitter and sweet oranges and differentiated from triple-sec due to a blend of cognac. The name is an homage to the Caribbean origins of this style of spirit.
Giffard is a French company specializing in a wide variety of liqueurs and eua-de-vie among other products. Some of those extra products are flavored cocktail syrups (or "sirop"). They are generally sweetened with pure cane sugar.