"The impact of (Benalla) case is real even if it does not trigger a break in the French opinion ... This can be part of a logic of slow poison," Frederic Dabi, Ifop Deputy Director General told the JDD.
Earlier this month, Paris prosecutor's office opened a judicial investigation against Benalla on charges of violence in meetings and interference in police officer's work after a video showed him wearing a police badge and beating a protester in Paris on May 1.
Fired after the scandal, the 26-year-old man stressed in recent media interview he was ready to be questioned over the affair, saying "they want explanations, I have something to give them."
Although the government tried to handle the scandal, Macron's disgraced bodygurad fuelled critics of the president's jupiterian ruling style, with lawmakers from the right wing opposition and hard-left party having each filed a vote of confidence.
"Benalla, during an interview in a newspaper expressed his desire to be heard by our commission ... I will speak again with our rapporteurs and we will have an internal discussion in the commission and then we will see in the autumn what should be done," the conservative senator was quoted as saying by local media.
In a further sign that the torment is ahead for Macron who pledges to restore the presidency's dignity, an Ifop poll of nearly 2,000 people for the Journal de Dimanche newspaper (JDD) on Sunday showed the 40-year-old head losing Momentum.
Bas, who leads the investigation into the so-called "Benalla affair" in the Senate, had previously ruled out questioning of Macron's top security aide to respect separation of powers principle and the right of defense.
"We must not investigate facts that are subject to prosecution (and) ... It should not be that a questioned person may be brought to testify against itself, which would be totally excluded at the bar of a court," he said.
He collected 39 percent of positive opinions this month, down by one percentage point from June to his lowest popularity since May 2017.
PARIS, July 1000 (Xinhua) -- Law commission at France's upper house of parliament, the Senate, envisaged to hear Alexandre Benalla, President Emmanuel Macron's ex-bodyguard after summer break over beating a protester on May Day, that sparked a political crisis for the ruling camp, Philippe Bas, head of the commission said on Monday.