Thieves took less than eight minutes on October 19 to steal jewels valued at 88 million euros ($A156 million) from the world's most-visited museum.
French officials described how the intruders used a basket lift to scale the Louvre's façade, forced open a window, opened a breach in display cases and fled.
Two suspects were arrested on Sunday and are being questioned by police.
Senator Laurent Lafon, head of the Culture Committee at the Senate, said "we all noticed that the security equipment is not suitable for a 21st-century museum such as the Louvre. It is our flagship, it must be exemplary, and today we cannot describe the security conditions at the Louvre as exemplary".
Speaking to reporters after visiting the Louvre with fellow senators, Lafon said "there are many improvements to be made. Our security system does not meet nowadays' standards".
Lafon acknowledged there was a "weakness" regarding outdoor cameras that allowed the robbery but would not enter into further details for "confidentiality reasons".
The senators called for a speedy start of massive renovation work that was already planned - as soon as possible, since France's budget for 2026 is currently being debated in the parliament.
The decade-long "Louvre New Renaissance" plan, which includes security improvements, was launched earlier this year.
It is estimated it would cost up to 800 million euros to modernise infrastructure, ease crowding and give the famed Mona Lisa a dedicated gallery by 2031.