American, Delta and United all have Chicago to Paris on sale at $499 to $509 round trip for departures from Sep 28-Oct 20. There are a few other cities on sale too like Amsterdam ($466-$481) and London ($533-$565). Brussels, Munich and Frankfurt are also in low to mid-$500s.
Frankfurt $564 United
Munich $551 United
Brussels $524 United
Barcelona $588 Delta
Dublin $599 Delta
Delta ticket for Air France Chicago ORD – Paris CDG nonstop flights
American Airlines Chicago ORD – Paris CDG – Charlotte CLT – ORD
Air Canada Chicago ORD – Toronto YYZ – London Gatwick LGW
United Chicago ORD – Amsterdam AMS (nonstop)
Loyalty Traveler – Hotel Promotions Guide
Hotel loyalty program points and miles promotions for Best Western Rewards, Club Carlson, Choice Privileges, Hilton HHonors, Hyatt Gold Passport, IHG Rewards Club, Marriott Rewards, Ritz Carlton Rewards, Starwood Preferred Guest and Wyndham Rewards.