France will lose no sovereignty if it returns to NATO's military command, alliance Secretary General Jaap de Hoop Scheffer told French lawmakers Thursday.

The NATO chief recalled that France and the Atlantic alliance had drawn closer over recent years, slowly moving back the decision by Charles de Gaulle in 1966 to withdraw from the integrated command.

"In doing these things France has lost nothing of her sovereignty -- any more than she would lose it tomorrow if she decided once again to take her rightful place in the alliance," Scheffer told a parliamentary committee.

President Nicolas Sarkozy is expected to formally announce in coming weeks that France will return to the North Atlantic Treaty Organisation's command structure despite strong opposition at home.

Critics say the decision amounts to a sea change in French foreign policy that will see Paris align itself further with the United States. There have been calls from opposition politicians for a referendum.

On Saturday, Sarkozy told an international security conference in Munich that the time had come for a national debate on France's return to NATO's top echelon.

"NATO today is no longer the NATO of 1966, not even that of 1995 when France first began her rapprochement," Scheffer told lawmakers.

A renewed alliance needs France, Scheffer told lawmakers, and France, western Europe's second military power, "would have everything to gain" from completely reintegrating NATO structures.

The French military would hold "very important positions" in a renewed alliance but such appointments would be conditional on Sarkozy first making a political decision to return to NATO's command, he added.

The United States has agreed to give French generals command of NATO's Allied Command Transformation in Norfolk, Virginia and a regional command headquarters in Lisbon, if Paris reintegrates.

The debate on the French role within NATO comes ahead of a summit in April in Strasbourg, in eastern France, and Kehl, across the border in Germany, that could confirm the new command structure.

France remains an important contributor to NATO operations despite standing outside its formal command structure. It has led the NATO peacekeeping mission in Kosovo and last year beefed up its contingent fighting in Afghanistan.

Foreign Minister Bernard Kouchner and Defence Minister Herve Morin are to appear before parliament next week to try to sell the proposal to sceptical lawmakers.

Returning to NATO command "would not lead to a real loss of independence but it would change France's image, which is not that of a country aligned on the United States," said Socialist deputy Jean-Michel Boucheron.

"Do we really want all of the world's nations to consider us just another Britain?" he asked.

Loic Bouvard, a deputy from the governing UMP party, said he did not fear for France's ability to act independantly but wondered "what is to be gained" from the decision.

Sarkozy has sought to portray the move as a boost for European defence, arguing that it would end longstanding suspicion of France for remaining outside of NATO's command structure.