Soap Dodger is a slur used to describe French in a derogatory way. From the French habit of not appearing to bathe regularly. Also France supposedly has the lowest per capita soap consumption in Europe.
The word Soap Dodger is a racial slur that has been used historically to degrade and dehumanize french. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to french. If you are unsure about whether or not it is appropriate to use the word Soap Dodger, it is best to err on the side of caution and avoid using it in any situation.