(Adds U.N. secretary-general's statement, paragraph 8)
PARIS, Sept 12 (Reuters) - Venezuela's government and opposition will hold a round of talks in the Dominican Republic on Wednesday, France's foreign minister said on Tuesday, warning Caracas that it risked EU sanctions if it failed to engage in negotiations.
Venezuela has been convulsed by demonstrations against leftist President Nicolas Maduro, accused by critics of knocking the oil-rich country into its worst-ever economic crisis and bringing it to the brink of dictatorship.
"I was happy to learn that dialog with the opposition would restart tomorrow in the Dominican Republic," Jean-Yves Le Drian said in a statement after meeting his Venezuelan counterpart, Jorge Arreaza Montserrat, in Paris.
Opposition leaders in Venezuela, however, said they had no knowledge of any talks starting this week.
"To be honest, I have no information on that," Enrique Márquez, head of opposition party A New Time, told Reuters.
"I have no idea why the French foreign minister said that. We are very surprised," added Tomas Guanipa, opposition legislator and secretary general of the Justice First party, at a news conference. "There's no type of conversation planned."
Le Drian said Wednesday's meeting would be under the auspices of Dominican President Danilo Medina and former Spanish Prime Minister José Luis Rodriguez Zapatero.
United Nations Secretary-General Antonio Guterres expressed his full support for the talks.
"The Secretary-General encourages the Venezuelan political actors to seize this opportunity to demonstrate their commitment to address the country's challenges through mediation and peaceful means," U.N. spokesman Stephane Dujarric said in a statement.
Maduro routinely calls for dialog with the opposition, but his adversaries see dialog as a stalling mechanism that burnishes the government's image without producing concrete results.
A dialog process brokered by Zapatero and backed by the Vatican in 2016 did little to advance opposition demands, which include release of political prisoners and respect for the opposition-run congress.
Many Maduro critics believe opposition leaders were duped in that dialog process, and have grown suspicious of Zapatero as an intermediary.
"This (dialog) is good news and I hope that it will rapidly lead to concrete steps on the ground," Le Drian said.
Like fellow-EU member Spain a few days earlier, Le Drian also warned Arreaza that if the situation continued there would be consequences.
"I told him that France was deeply worried by the political, economic and humanitarian situation in Venezuela," he said.
"I reminded him of the risk of European sanctions and the need to rapidly see evidence from Venezuela that it is ready to relaunch negotiations with the opposition and engage in a sincere and credible process." (Reporting by John Irish in Paris and Diego Ore and Brian Ellsworth in Caracas; Additional reporting by Michelle Nichols at the United Nations; Writing by Brian Love and Andrew Cawthorne; Editing by Leigh Thomas and Sandra Maler)