Goals from Clarck N'Sikulu and Modou Sougou in the second half secured a famous win for the hosts, and sees PSG’s unbeaten league run end at 26 games, one match shy of equalling the club record.
And Ibrahimovic was blunt about les Parisiens performance, which leaves them with a one-point lead at the top of the table over Lille.
“It was a bad game. We did not deserve to win,” he said to reporters.
“The team has not been good and we never found our rhythm. This is a good wake-up call. Every game is difficult and we must stay focused.”
However, PSG coach Laurent Blanc refused to blame his side for the setback, instead voicing his displeasure at the condition of the Parc des Sports pitch.
“We may think that we did not have all the ingredients to win, but in the first period, we had four or five clear chances,” he said.
“Even with Thiago [Motta], we would have struggled because the pitch was difficult. That's what upsets me a little. The conditions were very complicated."
However the 48-year-old did not attempt to take credit away from Evian for their triumph, though he was concerned that his side’s demanding schedule might be catching up with them.
“It is a bit difficult when we play every three days,” he added.
“But that does not diminish the merit of Evian. They played with heart, they [created] opportunities and if they had materialised, it could have meant more trouble. Congratulations to them.
“We did not create many chances. We may have regrets about the defeat, yes. But, in the first period, we could have opened the scoring. In the second, we played too bad to hope to win."