Rémoulade is a condiment invented in France that is usually aioli- or mayonnaise-based. Although similar to tartar sauce, it is often more yellowish, sometimes flavored with curry, and sometimes contains chopped pickles or piccalilli.

It can also contain horseradish, paprika, anchovies, capers and a host of other items. While its original purpose was possibly for serving with meats, it is now more often used as a condiment or dipping sauce, primarily for sole, plaice, and seafood cakes.

Remoulade is used in France, Denmark, Iceland, Faroe Islands, Germany, Sweden, Norway, Poland and in the United States, especially in Louisiana Creole cuisine.

According to Larousse Gastronomique, rémoulade is 250 ml (1 cup) of mayonnaise with 2 tablespoons mixed herbs (parsley, chives, chervil and tarragon), 1 tablespoon drained capers, 2 finely diced cornichons and a few drops of anchovy essence.

Some recipes use chopped anchovy fillets. The rémoulade used in céleri-rave rémoulade is not the same as the remoulades discussed in this article, but is instead based on a simple mustard-flavoured vinegar and oil dressing spiced with salt, pepper, and chopped green herbs.

Rémoulade is classified in French cooking as a derivative of the mayonnaise sauce.

More Info: en.wikipedia.org