Someone felt the need for a press release:
The Only Thing French About French's(R) Mustard Is The Name!
Robert T. French's All American Dream Lives On
WAYNE, N.J., March 18 /PRNewswire/ -- Recently there has been some confusion as to the origin of French's mustard. For the record, French's would like to say, there is nothing more American than French's mustard.
...
New Jersey-based Reckitt Benckiser Inc., the maker of French's mustard, is a leading North American manufacturer, marketer and distributor of household and food products.