The remains of two unidentified soldiers from the Garhwal Rifles were found in September 2016 along with their regimental insignia in a field near the north-western French town of Laventie, 70 kilometres from the Channel port of Dunkirk.
The remains of a British and a German soldier were also found by local authority employees working at the site.
France told India of the discovery and Delhi decided to send a team of four officials, including a brigadier from the regiment, to identify the soldiers and artefacts found with them and bring back their remains.
“We will try our best to identify them, although it will be difficult,” said Colonel Ritesh Roy of the Garhwal Rifles. “The bodies were buried for more than 100 years, so very little is left.”
The Garhwal Rifles, named after the eponymous region in the northern Himalayas, was raised in 1887 as part of the Bengal Army before it was incorporated into the British Indian Army.
It remains an infantry regiment in the Indian Army.
Soldiers from the regiment fought in World War I and World War II.
It lost 721 men in the first conflict and 349 in the second.
Two of its soldiers won the Victoria Cross, the highest military honour in the UK and the Commonwealth.
One of them, Gabar Singh Negi, was killed at the 1915 Battle of Neuve Chapelle, whose site is less than eight kilometres from Laventie, leading to speculation that the soldiers found last year were killed during that battle.
More than one million Indians served in World War I and more than 62,000 of them were killed.
Another 2.5 million served in World War II.
An Indian Memorial now stands at Neuve Chapelle.
Indian Prime Minister Narendra Modi visited it when he came to France in 2015.