If Celtic are found guilty, the suspended sentence of a one-match ban for their away fans will be automatically imposed.
There could also be further punishment, but that will be determined by Uefa’s control, ethics and disciplinary body – with an outcome unlikely until next week.
Uefa is also likely to investigate banners and chanting from the match in Birmingham.
Celtic manager Brendan Rodgers was asked about the implications of the smoke bomb after the game but refused to be drawn on the subject.
The Scottish champions were already assured of a place in the play-off stage of the new Champions League format before their 4-2 defeat against Villa.
Celtic were drawn against Bayern on Friday, with the second leg at Allianz Arena on 18 or 19 February after a first leg in Glasgow the previous week.
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