Which european nation might have decided to challenge the louisiana purchase territory in 1803

France was the country that sold the United States the Louisiana territory, so they could have just said "no you can't have our land." 

“destroyers for bases agreement in the destroyers for bases agreement between the united states and the united kingdom on september 2, 1940, fifty caldwell , wickes, and clemson class us navy destroyers were transferred to the toyalbnavy from the united states navy in exchange for land rights on british possessions.” i hope this you .