Agreed. Also ORD has outrageous parking fees and a 3 hour drive does take a good amount of gas. Even if the IND or CVG flight is a little more expensive (which depends when you book of course) then IND would still be cheaper in the long run as it costs money just to get to ORD. I found IND-CDG prices that were pretty good if you look at the right time. It's just all about timing at that point.I'm taking also taking this flight next week on the way to Berlin.
If you are flying for business and your company is paying for it, I don't understand why you would fly out of ORD or CVG.
Leisure travel is different, but if the cost isn't prohibitive I would still go with IND.