Frenchman Platini, 61, was head of Uefa until his ban for breaching ethics rules over a £1.3m "disloyal payment".
Uefa is meeting to select the former France midfielder's successor.
It asked Fifa for permission for its ex-leader to attend the gathering.
"The Fifa ethics committee has informed Uefa that Michel Platini will be allowed to address the 12th Extraordinary Uefa Congress in Athens on 14 September," it said in a statement.
"A request for Mr Platini's attendance had been recently made by Uefa and we welcome this decision," it added.
The ethics committee of world governing body Fifa handed down an initial eight-year ban for Platini and Fifa's then-president Sepp Blatter last year.
It related to a payment of 2m Swiss Francs Blatter made to the Frenchman in 2011.
The two have always denied wrongdoing and said the payment was made for consultancy work Platini had carried out for Blatter between 1998 and 2002, and that they had a "gentleman's agreement" on when the balance was settled.
But the ethics committee felt the pair had demonstrated an "abusive execution" of their positions.
Charges included conflict of interest, false accounting and non-co-operation, with investigators submitting a file of more than 50 pages.
The bans were later reduced to six years on appeal to Fifa, then four years in a further appeal to the Court of Arbitration for Sport.
The issue is still under investigation by Swiss prosecutors.
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Michel Platini has been given permission to address European football's governing body Uefa when it meets this week - despite the former president being banned from all football activity.