Perhaps an easy question. I have two maps, one of the French Empire c. 1811 the other of Eastern Europe and the 1813-1814 Campaign (both at this site: http://www.emersonkent.com/wars_and_battles_in_history/napoleonic_wars.htm). They show the border of the Swiss Confederation and France at different locations, although both show Neuchatel. One (1811) has France extending all the way to the Aare River making Solothurn on the border, while the 1813-1814 map shows Switzerland extending north and west up to about the Doubs River. It doesn't include however the big pocket in which Porrentruy sits today suggesting that it was part of France in 1814 (pre Napoleon's defeat). This is further confused by Weil who talks about the IIIrd Corps crossing into France for the first time at Delle which is about 10-12 km nnw of Porrentruy. The border definitely changes in 1814.

v/r Greg