Honestly, my personal preference would be to take the plane to CDG
, then take the train to Bourges from Paris Austerlitz station - it's only a 2hr train ride from Paris if you catch one of the direct Intercités trains, and it'll be far more cost-effective. Tours airport is badly served, and is still 80 miles away from Bourges - ORY
is ~115 miles I think from Bourges so flying into there and getting out to Bourges will be easiest I think. I visit the central area of France fairly often, it's an area that's poorly served both by air and by rail, so it won't be the easiest to get to.