December milling wheat

on the Paris-based Euronext exchange unofficially closed down 0.75 euros, or 0.4pc, at 180.75 euros ($202.7) a tonne, as it pulled further away from a near two-week high of 184.25 euros struck on Monday.

The contract was underpinned by chart support at 180 euros, dealers said.

The advancing French wheat harvest, which is now underway in the northern half of the country, was continuing to show decent yields and mixed protein readings, traders said.

After production expectations were trimmed following a late-June heat wave, harvesting was encouraging some market participants to raise forecasts again to 38 million tonnes or higher, they said.

France's farm ministry this month forecast the crop at 37 million tonnes, up from around 34 million last year.

Uncertainty over the size of the harvest in Russia, the world's top wheat exporter, following recent hot, dry spells was also helping to underpin Euronext, traders added.

In Germany, premiums in Hamburg were unchanged, remaining under Paris as a new forecast intensified expectations of a large German harvest this summer which will be difficult to sell in export markets.

Standard bread wheat with 12pc protein for September onwards delivery in Hamburg was offered for sale unchanged at 3.0 euros under Paris December.

Buyers were seeking at least 4.5 euros under.

Germany's wheat harvest is set to rise sharply from the drought-damaged crop in 2018 but a heat wave in recent weeks means crop forecasts have been scaled back, Germany's association of farm cooperatives (DRV) said on Tuesday.

The country's wheat crop will increase 17.7pc on the year to 23.85 million tonnes, the association said in its latest harvest forecast. The association had forecast Germany's 2019 wheat harvest at 24.70 million tonnes in its previous harvest report in June.

"The forecast confirmed that the heat wave in late June will not bring major changes to harvest expectations," one German trader said.

"It looks like Germany is facing a big harvest which will be difficult to export in coming months as Russia and other Black and Baltic sea exporters also have good harvests and are offering cheap prices."

Meanwhile, all wheat exporting countries are currently facing slack purchasing demand, he said.