Location: Marriott Brussels Grand Palace
Dates: 9/22-9/26/2015
Marriott Rate: ~200 Euros/night
LNF Rate: ~$173/night
LNF Rate Website: Using the largest meta search travel engine you can find a half a dozen places with the lower rate

Notes: There are cheaper advanced rates but the cheapest fully refundable rate was ~200 E/night.

I just submitted a LNF request after booking through Marriott.

Please be gentle - this is my first post on an LNF find. :-)