The presidency confirmed Thursday it had written to Alexandre Benalla in the last few days demanding more details of his business trips to several African countries and telling him not to claim any links to the government.
Government officials are worried he may be profiting from his former insider status.
The news site Mediapart said Benalla was still travelling on a French diplomatic passport received as part of his former job.
The foreign ministry said on Thursday that it had asked Benalla in July to hand in the two diplomatic passports and was considering further steps.
Benalla attacked protester
The Benalla scandal – as it has become known – has reared its head again at the worst time for Macron’s presidency as other policy issues have also piled up, including a stream of anti-government demonstrations staged by “Yellow Vest” protesters.
The scandal erupted in July after a video surfaced of Benalla, 27, viciously beating a May Day protester. Macron fired him, but was accused by political rivals of acting too slowly and being out of touch.
Visited Chad's president before Macron
Two weeks ago it emerged that Benalla travelled to Chad in early December and met with President Idriss Deby, shortly before Macron himself paid a visit to the African country.
Benalla said he was accompanying a "foreign business delegation" promoting major Middle Eastern companies.
But the fresh revelations have sparked questions in France over why he was granted such high-level access to an African leader.
Macron's office told AFP that Benalla had not informed the presidency of the trip until afterwards.
Macron 'forbids you from claiming ... support from the presidency'
In a strongly worded letter to Benalla dated December 22, Macron's office chief Patrick Strzoda warned the ex-bodyguard against divulging any confidential information gleaned during his previous job at the French president's side.
"Let us be clear: we forbid you from claiming you have any kind of recommendation or tacit support from the presidency," Strzoda wrote.
"With regard to your current personal activities, we ask you to ensure they are conducted with strict respect for the confidentiality and ethical responsibilities of your time in this office."
Strzoda further demanded that Benalla provide details of "personal and private trips" during his time working with Macron, including any payments.
The presidency would be forced to respond to any previously undisclosed business dealings deemed "incompatible" with his former role, Strzoda warned.
Benalla 'won't keep quiet'
Benalla, who is subject to a judicial investigation, has denied boasting of insider influence to win work after his sacking and accused members of Macron's entourage of "trying to wreck" his life.
"I won't keep quiet any longer," he said in a statement.
The ex-aide has also been quoted in the French press as saying he was “shocked and scandalised” by suggestions that he has acted inappropriately.
Le Monde newspaper reported that Benalla had met in October with Congo's President Denis Sassou-Nguesso as well as with top officials in Cameroon as part of a business delegation.
“Today I’m a consultant. I’ve been to around 10 countries in Africa,” he told the leading French daily. “I’m not going to stop doing what I’m doing.”
Macron’s approval ratings fell below 20 percent in early December, even as he responded to the Yellow Vest protesters' anger with an array of measures, including shelving an unpopular fuel tax hike and raising the minimum wage.