Sauce charcutière is a classic French compound sauce known for its tangy, savory flavor, specifically designed to accompany pork dishes. It is traditionally made by enhancing a Sauce Robert base (a sauce made from onions, mustard, and white wine) with finely chopped cornichons (gherkins). 
A “500g” reference typically refers to a commercial, ready-to-use version or a recipe yield of this savory sauce. 

Characteristics and Composition
Flavor Profile: Sharp, tangy, and rich. The acidity from the white wine, vinegar, and cornichons cuts through the fat of pork.
Key Ingredients:Base: Demi-glace or beef stock.
Aromatics: Onions or shallots, white wine, garlic.
Mustard: Dijon mustard.
Tang: Finely chopped cornichons.
Usage: It is the quintessential pairing for grilled or sautéed pork chops, sausages, and roast pork. 

What “500g” Means
In a culinary context, 500g of sauce charcutière is enough to serve roughly 4–6 people, as it is a concentrated, intense sauce rather than a light gravy. 
Retail/Commercial: You may find this in specialized European food markets as a prepared, jarred sauce.
Homemade Recipe: A typical home recipe aiming for 500g of finished sauce would start with roughly 400-500ml of beef/veal stock, reduced down with white wine, onions, and finished with a significant amount of mustard and chopped pickles. 

Origins
The name charcutière translates to “pork butcher,” highlighting its traditional use as an accompaniment to sausages and pork products in French cuisine. It is a staple at Parisian bistros, often made in the same pan used to cook the meat to incorporate caramelized pan drippings.