As the French Senate debates a controversial new law that would make it illegal to deny the killing of Armenians by the Ottoman Empire was a genocide, supporters and opponents of the bill demonstrated outside the Senate building in Paris.

The row has been rumbling on, causing diplomatic tension between France and Turkey.

If passed, anyone breaking the law can be fined up to 45,000 euros and sentenced to a year in prison.

France’s Parliamentary Relations Minister Patrick Ollier said: “Denial is the ultimate insult to the collective memory that we share. Those who encourage this oversight only fuel the hatred that could and should have decreased over time. Our society must fight against the poison of denial, and that’s why I propose this text that is intended to fill a legal vacuum.”

Outside the French embassy in Ankara, angry people held banners protesting French imperialism. Some accuse French President Nicolas Sarkozy of trying to curry favour and win votes from the large ethnic Armenian population in France, which numbers more than 500,000.

“We don’t understand how Mr Sarkozy can allow this decision to be made only for his own political calculations. It is a decision that should be made by historians,” said Turkey’s Prime Minister Recep Tayipp Erdogan.

More than 1.5 million Christian Armenians were killed in what is now eastern Turkey during the First World War. Armenians claim it was a deliberate genocide, but Turkey said both sides suffered heavy losses.