France's president and prime minister were absent from ceremonies in Paris on Friday marking the 200th anniversary of the Battle of Austerlitz.
Overseas groups have attacked celebrations of Napoleon's victories
In 1805, Emperor Napoleon Bonaparte crushed a Russian-Austrian army on land that is now the Czech Republic.
Officials are quoted as saying that President Jacques Chirac and Prime Minister Dominique de Villepin had never planned to attend.
The controversy follows recent violence in France's suburban ethnic ghettos.
It also coincides with a wider debate about the country's identity and role in Europe and the world.
Groups representing the inhabitants of several French overseas territories have strongly criticised what they call the "official commemoration of Napoleon" - accusing him of genocide against colonial peoples. They plan to hold a public protest on Saturday.
Fought on a cold and misty December morning 200 years ago, the Battle of Austerlitz is widely regarded as Napoleon's masterpiece.
Officials say the French leaders were not due to attend the ceremony
Earlier in 1805, Britain, Austria and Russia had formed a military alliance - part of a titanic 20-year struggle, which pitted revolutionary France - and its successor, Napoleon's French Empire - against Europe's other major powers.
After defeating the Austrians at Ulm in southern Germany, Napoleon seized the Austrian capital, Vienna. A combined Austrian-Russian army assembled 100km to the north.
Though outnumbered, Napoleon was keen to bring on a decisive fight. He deliberately weakened his right flank, tempting the Allies to try to encircle him - extending their own lines in the process.
He then struck hard at the centre, splitting the enemy forces and driving their left wing onto a frozen lake. The Austrians surrendered - and the surviving Russians marched back home.
The subsequent peace treaty gave France almost total control of Italy - and established a French protectorate over most of Germany. It had been a terrible year for the Allies - the only consolation being the British naval victory off Trafalgar.
Hero or villain?
Eventually, of course, Napoleon over-reached himself. The French "Grand Army" gradually lost its winning edge - in aggression, flexibility, speed and logistical backup. After a score of further major battles, Napoleon was finally forced to abdicate in 1815. With his downfall, the prospect of a French-ruled Europe disappeared as well.
France has had to deal with riots and arson in the suburbs
Foreign visitors to Paris are often struck by the apparent reverence in which Napoleon - dictator and warlord - is still held. Triumphal arches, victory columns and Napoleon's magnificent tomb - are all prominent features of the Parisian landscape. Naturally, the French also emphasise Napoleon's role as enlightened law-giver, moderniser and statesman.
To a nation once rocked by revolutions and bitter political feuds - between monarchists, republicans, communists and fascists, democrats and authoritarians - the Napoleonic legend offered a kind of unity.
It is this Napoleon that is now being challenged by several groups from France's surviving overseas territories. It was Napoleon, they say, who reintroduced slavery in 1802 - eight years after its abolition during the French Revolution.
It is was also Napoleon who despatched an army of 60,000 to Haiti, authorising the use of sulphur dioxide gas against rebel slaves - and Napoleon who introduced legislation forbidding "people of colour" to enter France.
Such complaints might have made less of an impression in the past. But France today is in an introspective mood. Its version of social integration - based on the notion that immigrant communities would assimilate completely to mainstream French culture - does not appear to be working.
Its model of the social-welfare state appears to be foundering amid high unemployment and slow growth.
It sees its influence waning in an expanded European Union - but has also failed to establish a co-operative relationship with the new EU members in Central and Eastern Europe.
The French language continues to decline as a medium of international communication.
The commemorations on Friday - including light shows, honour guards and the unfurling of the standards of regiments that fought at Austerlitz - will not disguise the underlying unease.