"I went into depression, I was ashamed to be paid to do nothing," he told AFP. "The worse part of it was denying this suffering," he said. He was fired in 2014 after seven months' sick leave.
He is seeking over €360,000 (NZ$589,497) in damages and missed pay, which included holiday pay and missing out on a potential promotion.
Ahead of an employment tribunal hearing on Monday, Montasser Charni, his lawyer, said the company's aim was to bore him to death so that they could fire him without redundancy payments or other compensation.
However, Jean-Philippe Benissan, a lawyer for the company, said there were serious inconsistencies in his claims for which he had "no proof", and that he had previously claimed to be suffering from the reverse - "burn out" - only to change tactics.
"He never said anything about being bored during the four-year period. And if he actually had nothing to do over these years, why didn't he mention it?" the lawyer added.
While the term "bore out" is not recognised by French law, Sylvain Neil, a labour law specialist said that France's higher court had to date recognised 244 cases of employees being "intentionally sidelined", which it ruled was tantamount to "moral harassment". One French researcher estimated that around 30 percent of French workers suffer from "bore out", reported France Info.
Jean Claud Delgènes whose firm Technologia specialises in employee risks, said the condition can strike when a staff member feels stuck but doesn't dare risk changing jobs in today's sluggish French labour market.
This is not the first time lack of work has hit the headlines in France.
Last year, it emerged that SNCF, the state rail operator, had paid employee Charles Michel more than €5,000 a month for 12 years, plus holiday bonuses, despite the fact he had not worked a single day in that time. He then demanded a further €500,000 compensation for missing out on a promotion.