The ratings slip reversed a small improvement in the previous week, and may indicate that growing conditions in the European Union's biggest cereal producer remain mixed despite rainfall and warmer temperatures this month that broke a dry, cold spell in April.

Strategie Grains analysts on Thursday cut their monthly forecasts for 2017 production of soft wheat and other cereals in the EU, factoring in weather damage to yield potential in countries including France and Spain.

However, FranceAgriMer's latest ratings for other cereals suggested a stabilising in crop conditions since a sharp decline during April.

In its weekly update, the office estimated that winter barley ratings were stable on the week at 67 percent good/excellent as of Monday, while the equivalent spring barley ratings edged up to 78 percent from 77 percent.

The good/excellent score for durum, the wheat variety used in pasta, rose to 67 percent from 64 percent.

The ratings for wheat and barley were still well below the levels a year ago, although crop conditions in 2016 deteriorated dramatically from late May due to torrential rain, leading to the worst harvest in three decades.

Storms this week which ended a short hot spell brought heavy rain to parts of France, although crop observers are watching to see how much moisture reached very dry areas with shallow soil.

Sowing of grain maize was virtually over, with 99 percent of the expected area now sown, ahead of the 88 percent progress seen a year earlier, FranceAgriMer said.

In its first rating of this year's French maize crops, it estimated that 86 percent were in good or excellent condition, compared with 85 percent a year earlier.