The scandals at Paris City Hall were becoming too dangerous, the attacks and counter-attacks too personal.
After allegations of corruption in President Jacques Chirac's Rally for the Republic (RPR) moved disturbingly close to the head of state, his cronies rounded on the Prime Minister, revealing that Mr Lionel Jospin accepted a government salary when he was not working.
This week's political mud fights turned the smooth "cohabitation" of Mr Chirac and Mr Jospin into sniper alley. On the brink of full-scale war, the two leaders yesterday pulled back and issued a joint appeal for a ceasefire.
The President and the Prime Minister wished to express "their concern about the excesses that risk upsetting French political life to the detriment of democracy", the statement by the Elysee Palace said. "This is an appeal for calm, reason and serenity," the President's office explained.
Mr Chirac's 1977-1995 term as mayor of Paris is an unexploded time bomb. Alluding to investigations of misuse of taxpayers' money by the RPR, the Justice Minister, Ms Elisabeth Guigou, told French radio last weekend: "Like all Frenchmen, if he has committed offences, the President of the Republic can be brought before the tribunals."
The Elysee was still reeling from Ms Guigou's comment when it was hit with a double whammy. In an interview with Le Parisien, the former director of personnel at Paris City Hall revealed that 300 relatives, friends and RPR party faithful received 100 million francs (£11.9 million) in municipal salaries for emplois fictifs - phoney jobs - while Mr Chirac was mayor.
Meanwhile, Mrs Xaviere Tiberi, the wife of Mr Chirac's chosen successor as Mayor of Paris, Mr Jean Tiberi, was held for eight hours by Versailles judiciary police in connection with the Ffr 200,000 (£23,809) she received for a mostly plagiarised 36-page report for the Essonne Council.
Mr Tiberi then went on radio and television to proclaim his indignation at his wife's treatment. Mrs Tiberi "knows everything about political life," he said in a scarcely veiled threat she might talk. But, he promised, "she will not crack". As for his own position: "I was elected and I shall remain Mayor of Paris. I am convinced of it. I am untouchable," he said, describing the investigation of his wife's affairs as "an operation of destabilisation" aimed at President Chirac.
Mr Tiberi was particularly outraged that Judge Laurent Dave nas, who is pursuing Mrs Tiberi, dared to publish her report in his book Letter from the Himalayas. In November 1996, the then Justice Minister, Mr Jacques Toubon, dispatched a helicopter to the Himalayas, where Mr Dave nas was trekking, to ask him to block the Tiberi investigation.
The same Mr Toubon has tried for the past two months to overthrow Mr Tiberi as Mayor of Paris. Their quarrel also came to a head this week, when the RPR presented them with an 11-point "peace plan" and demanded that they stop fighting or be thrown out of the party - an ultimatum denounced yesterday by Mr Toubon as a diktat.
Mr Chirac and his advisers met in the Elysee to contemplate the disaster and concluded that the ruling Socialists, the judges and the media were plotting to destroy the President. So the RPR went for Mr Jospin in parliament, accusing him of having held an emploi fictif just like the hundreds of ghost wage earners at City Hall.
From 1994 until 1997, Mr Jospin, who has ambassador rank in the civil service, received Ffr 32,850 (£3,910) each month from the Foreign Ministry, although he had no posting. Mr Jospin's acceptance of the salary was perhaps ethically questionable, but unlike the RPR's financial arrangements, it was legal.