Following MP François de Rugy, who left the EELV on Thursday, its leader in the Senate, Jean-Vincent Placé, announced he was leaving a party he described as a "dead star", "sectarian" and "turning to the far left".
Nobody was surprised at Placé's departure, which was predicted by pundits after his criticisms of the EELV last week.
Party loyalists tried to play down the departure of members who regret its two ministers leaving the government in 2014 and want to support Hollande in the 2017 presidential election.
The defectors are angry at a decision to form alliances with Jean-Luc Mélenchon's Left Front in some areas in December's regional election, claiming that it plays into the hands of the far-right Front National.
Mélenchon himself called the departures a "clarification" by the "right wing of the Greens".
But only 12 of the 18 EELV MPs elected in 2012 are still in the party and others could leave, as the party's vote continues to decline.
That is good news for the Socialists, who meet in the western city of La Rochelle this weekend, since the government was weakened by the Green's departure and they would like their backing in the regional poll.
Indeed, Placé made his remarks in La Rochelle, where he was to attend the summer school and was seen supping champagne with Socialist activists in a restaurant on the old port at 2.00am, according to Le Monde newspaper.
The Socialists hope to pick up Green voters and credibility on the left thanks to this year's energy transition law and the Cop21 international climate change conference to be held in Paris in December.
Hollande himself is believed to have high hopes for that conference; he would like it to put him into the history books as the man who brokered the deal to save the planet.
But there was bad news for the Socialists, too.
Economy Minister Emmanuel Macron, a former merchant banker who is not a party member, managed to bring the government's own internal divisions back into the spotlight this week when he appeared to question the value of the 35-hour working week while addressing the bosses' union, Medef.
Prime Minister Manuel Valls was quick to say that there is no question of scrapping it, adding that there are plenty of ways to gain exemptions, anyway.
But the party's left, who held a get-together ahead of the summer school, took it as further evidence of the government's rightward, pro-big business drift.
And supporters of Martine Aubry, the powerful mayor of Lille who introduced the law when she was labour minister, said Macron was trampling on the party's legacy.
The summer school will discuss the Cop21 conference, with the Green's leader, Emmanuelle Cosse, invited to speak at one seminar.
It will also address strategy for the regional elections, which will take place at the same time, and, on a more exalted level, the republic, a debate that will centre on what "liberty, equality and fraternity" mean today.
Meanwhile, unemployment stubbornly refuses to fall and the latest opinion poll puts Hollande behind Front National leader Marine Le Pen and mainstream right leader Nicolas Sarkozy if the first round of the presidential elections were held today.