Before the attack, he called the lines in the 2018 French Open women's final and 2021 men's final, plus prestigious ATP finals in Monte Carlo and Bercy.

In 2021, he was awarded white badge status - putting him in the second tier of top international officials.

It has been an arduous road back for Feron, whose progress is being carefully managed by French Tennis Federation's officiating bosses.

Last year, Feron returned to Roland Garros in an exhibition match during the Yannick Noah charity day.

This year, he worked at an ATP Challenge event in Bordeaux, which he said helped "improve his eyes" on the ball.

His level was deemed good enough for the French Open, starting on the outside courts of the main-draw events before being promoted to Simonne Mathieu - the third show-court - and then Chatrier.

Feedback about a line judge's performance comes from a technical supervisor assigned to each court and the chair umpire of the match.

"We need to have excellent officiating on all courts, thats the first thing for us," Jean-Patrick Reydellet, the French Open's chief of officiating, said.

"Lucas is there because he deserves it. Not because he is a wheelchair official. For us, this is very important."

Feron's quality of speech is not at the same level it was before the attack.

As well as having physio for his injuries four times a week, he continues to work with a speech therapist.

Therefore, he uses a microphone headset on court to amplify his calls to the chair umpire.

"He didnt lose what he can see. Its just the voice which needs to readjust," said Reydellet.

Seeing a line judge in a wheelchair at a Grand Slam for the first time has brought attention.

Djokovic hailed Feron on Twitter (formerly X), with the 24-time major champion saying it was "wonderful" to see him working.

"Very cool, very cool. I did not know this," said Feron, who looked amazed and broke into a broad smile.

Then, as ever, his professionalism kicked in and he stressed his impartiality.

"But I cannot tell you if he is a good player or not because I am an official! I can say I think he is a good person."