ZURICH (Reuters) - Cartier jewellery owner Richemont on Thursday reported a 10% increase in constant currency sales during the three months to the end of December, a strong early indicator for the performance of European luxury companies over the all-important holiday season.

Sales at actual rates increased to 6.2 billion euros ($6.37 billion), said the company, which also owns high-end Swiss watch brands Piaget, IWC and Jaeger-LeCoultre.

At constant exchange rates - which removes the impact of currency fluctuations - sales increased by 10%. This was much better than 1% increase expected by analysts in a consensus cited by RBC.

($1 = 0.9727 euros)