Two French history enthusiasts have launched a search in Australia to find relatives of a World War I soldier whose identification tag was found buried in a French field.

Commerce student Valentin Henon, 18, found the battered disc while metal detecting in a paddock near his home in Campagne-les-Boulonnais, in northern France.

The small metal medallion is stamped with the name McCarthy, C. and the service number 827.

Mr Henon described his excitement at finding the dog tag.

"I have a passion for militaria and have always wanted to find a military plate," he said.

Enlisting the help of fellow history fan Philippe Clerbout, the pair discovered the dog tag belonged to Cyril Michael McCarthy, a private in 'C' Company, 33rd Infantry Battalion of the Australian Imperial Force.

McCarthy, a shearer, enlisted in December 1916 in Narrabri, becoming a member of what was known as "New England's Own" for the large majority of soldiers from that region in its ranks.

Arriving in France in 1916, McCarthy and his fellow diggers fought at Messines and Passchendaele, before a gunshot wound to the hand in 1918 led to him being shipped home.

Now Mr Clerbout is keen to present the dog tag to Cyril McCarthy's family.

"What motivates me in this research is the duty of memory. All these soldiers fought for our freedom. They left their families thousands of miles between them and unfortunately, many did not return home," he said via an interpreter.

Mr Clerbout is involved with a group of French metal detector users interested in the history of their region.

Since its inception in 2009, the group has unearthed jewellery, wedding bands and agricultural equipment.

Mr Clerbout recently reunited US veteran Willie Wilkins with dog tags the GI lost during a mission in France in 1944.

Hope Private McCarthy's grandchildren will be found

Soldiers on the Western Front with a captured machine gun. ( E02690 : AWM )

With the help of Australian amateur medal enthusiast, Lieutenant Colonel Glyn Llanwarne OAM, Mr Clerbout is hoping for a similar outcome.

Lt Col Llanwarne understands the importance of medals, having received a total of nine himself for service with the Australian Army.

His organisation Lost Medals Australia tracks down the rightful owners of medals passed to him.

He has made various attempts to locate McCarthy's descendants and has learned he had three sons: John Michael, Leo and Daniel Cyrill, all of who have now died.

His hope is that their descendants will come forward to claim the dog tag.

"I have the names of Cyril's grandchildren, who live in NSW. Finding their exact contact details is proving elusive," he said.

His website lists the names of 200 service personnel he is attempting to locate with the hope of returning their medals.

Most medals handed to him have been found in Australia.

"Some are found in the gutter after Anzac Day, others are recovered from robberies or discovered by charities in suitcases of donated clothes.

"I've received very few items that have been found like this dog tag," he said.

According to the Australian War Memorial website, WWI dog tags were made of fibreboard. Lt Col Llanwarne says this material deteriorated with sweat and rain so soldiers made their own from scrap metal.

"In some camp areas there was a trade in this type of product and local tradesmen would make them," he said.

If you think you can help reunite this dog tag with Cyril Michael McCarthy's family, please contact Glyn Llanwarne at llanwarne80 [at] hotmail.com.