CBOT September wheat settled down 1-3/4 cents at $4.06 per bushel. K.C. hard red winter wheat and MGEX spring wheat futures also closed lower.
CBOT wheat traded higher at times, underpinned by fund short-covering and worries about the size of the French wheat harvest.
Consultancy ODA lowered its estimate of the French soft wheat crop to 28.2 million tonnes, down 2.2 million from its previous figure, pegging production at its lowest in 28 years in the European Union's biggest wheat grower.
Russian wheat export prices rose last week, boosted by a weak crop in Western Europe, analysts said.
The USDA reported export inspections of US wheat in the latest week at 662,373 tonnes, topping a range of trade expectations for 450,000 to 600,000 tonnes.
Iran said it will stop importing wheat because of high domestic production and plans to export wheat by March 2017, a senior Iranian official was quoted as saying by Students News Agency ISNA.