This Ukrainian unit is finishing a four-week course on infantry combat, with their numbers, identities and location kept secret for security reasons.

With an average age of between 35 and 40, the recruits include called-up reservists, newly-mobilised civilians and volunteers. Most have never seen battle.

The troops set off one wet November morning for a two-day exercise under their own officers' command, aimed at putting into practice the knowledge gleaned from their hosts.

French instructors and interpreters march alongside to correct mistakes and offer further tips.

Part of a 1.7-billion euro ($1.8 billion) support effort by Paris, France's training falls under the European Union's Military Assistance Mission backing Kyiv.

One of 24 countries offering training and instructors, France should put 7,000 Ukrainian troops through courses on its own territory and in Poland by the end of 2023.

"We go over all the basics of the soldiering profession, so taking care of a weapon, fighting in different types of terrain: urban areas, open areas and trenches," said Lieutenant Colonel Even, a French officer commanding the programme who can only be identified by his first name, like others who spoke to AFP.

- Avoid friendly fire -

With fighting against Russian forces taking a heavy toll on Ukrainian troops, first aid is high on the agenda.

"Take care of the wounded man! Bring him to the rear!" one instructor shouts in a muddy trench Ukrainians are battling to reclaim from the enemy forces -- represented here by French soldiers.

One of the men immediately ties a tourniquet around the arm of his supposedly wounded comrade.

The Ukrainians' mission "has been quite successful, in the sense that the units coordinated well," said another French officer, Captain Michel.

"In complex terrain like this, a trench network spreading off in several directions", avoiding friendly fire is the "key" point, he adds.

- 'Fear and motivation' -

In a nearby mock-up of a village, there is fierce fighting after an aggressive counter-attack by the enemy.

"The Ukrainian troops have managed to push back the enemy, and now they have to win back the lost ground house by house," says Captain Remi as three Ukrainian soldiers storm a house with red shutters, throwing dummy grenades.

Although the trainees are barred from speaking to the media themselves, the French officers say they value the urban fighting exercises.

"There's always a mix between fear of getting to the front line and the motivation and desire to defend their land. You feel that duality on a daily basis," Lieutenant colonel Even said.

"They're very keen to learn, always asking to learn new ways of doing things," he added. "It's a pleasure to work with such motivated recruits."

Despite the warmth between the two armies "we have to keep a certain distance, because we know what's waiting for our Ukrainian comrades at the front," he said.

French instructors are forbidden from exchanging phone numbers with the Ukrainian trainees.

"We have to avoid creating ties that are too strong, that could weigh on our soldiers' morale," Even said.