Alexandre Benalla said Monday that the passports were returned to him in October "by a salaried person at the Elysee."
He didn't name the person, saying only that the still-active passports were handed to him in a street, and he used them 23 times.
The commission is probing what authorities have described as state "disfunction," surrounding the mysterious role of the one-time aide.
Benalla was handed preliminary charges last week for abusive use of the documents. He was charged earlier for allegedly violent behavior at a May protest.
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