October finished down $0.9 at $234.6 in volume of 2,952 lots, having traded in a range between $234.5 and $236.4.
December closed down $1.2 at $242.6 in volume of 1,619 lots.
"We have seen some hedge selling against the EU restitution tender, with the market following New York," one trader said.
The European Union sold 84,000 tonnes of white sugar at a maximum rebate of 47.175 euros per 100 kg at Thursday's tender, traders said.
London traders noted light trade buying early in the session, as well as rolling between the October and December contracts.
Traders talked of a possible tolling operation involving three merchants with a Dubai refiner in which the refiner would store some 500,000 tonnes of September-October sugar at a discount and return it to the merchants for December-January shipment. Confirmation was not immediately possible.