Where does the phrase "Pardon my French" come from? Are there any equivalents in other languages?

I believe it all started because there's the large amount of French cuss/swear words. My old roommate was a French speaker, and she said there's no polite way of saying many words in French (**** is just ****...not poop). Also, many people have adopted the habit of using French cuss words instead of English ones, just to be cool.