Turkish President Abdullah Gul has called on France to halt plans for a law criminalising the denial of the mass killing of Armenians by Ottoman Turks during World War I as genocide.
The French lower house of parliament is due to consider a bill that proposes a one-year prison term and a heavy fine.
Armenians say up to 1.5 million people died during mass deportations. Turkey puts the figure at closer to 300,000.
In a statement, President Gul said the proposed legislation, set to go before the National Assembly on Thursday, denied Turkey the freedom to reject unfair and groundless accusations . He also suggested that France was jeopardising
centuries of friendship because of small political calculations .
Last week, Turkish Prime Minister Recep Tayyip Erdogan wrote to French President Nicolas Sarkozy warning him that bill was hostile and directly targeted Turkey and Turks living in France. Such steps will have grave consequences for
future relations between Turkey and France in political, economic, cultural and all areas, and the responsibility will rest with those behind this initiative, the Anatolia news agency quoted him as saying.
A delegation of Turkish MPs and businessmen has travelled to Paris to lobby against the bill and was due to meet Sarkozy's diplomatic adviser, Jean-David Levitte, and French Foreign Minister Alain Juppe.
The French Senate has approved a controversial bill that makes it a criminal offence to deny that genocide was committed by Ottoman Turks against Armenians during World War I. The Senate approved the bill by 127 votes to 86.
The measure will now be sent to President Sarkozy for final approval.
The bill's passage in the lower house caused major tensions with Turkey. Ankara froze ties with France after the vote last month and promised further measures if the Senate backed the proposal.
The BBC's correspondent in Istanbul, Jonathan Head, says stronger Turkish measures could include the withdrawal of ambassadors and creating more barriers to French businesses in Turkey.
In the first reaction from Ankara, Justice Minister Sadullah Ergin condemned the bill. He told the CNN-Turk television channel:
The decision made by the Senate is a great injustice and shows total lack of respect for Turkey.
The Turkish embassy in Paris warned that if President Sarkozy approved the bill, the damage done to relations between the two countries would be permanent.
French President Nicolas Sarkozy has ordered his government to draft a new law punishing denial of the Armenian genocide after a top court struck down a previous bill.
The Constitutional Council earlier ruled the law backed by Sarkozy infringed on freedom of expression. The bill, which covers the mass killing of Armenians by Ottoman Turks during World War I, was passed by both houses of the French parliament.
Turkey welcomed the ruling. But now Sarkozy seems set on re-opening Turkish antagonism. Noting the great disappointment and profound sadness of the law's backers, Sarkozy's office wrote in a statement:
The President of the Republic considers that [genocide] denial is intolerable and must therefore be punished. He has asked the government to prepare a new draft taking into account the decision of the Constitutional Council.