The disciplinary proceedings relate to last month's quarter-final first-leg clash between the two teams at the Parc des Princes, which PSG won 3-1 before going out on away goals following a 2-0 defeat at Stamford Bridge.
UEFA have not detailed the accusations but confirmed that they are in connection to offenses concerning "racism, other discriminatory conduct and propaganda."
A UEFA statement read: "Disciplinary proceedings have been opened against PSG on 16 May 2014 for alleged offences concerning "racism, other discriminatory conduct and propaganda" at their UEFA Champions League quarter-final played against Chelsea in Paris.
"The UEFA Control and Disciplinary Body will decide on the matter on 17 July 2014.
"We do not make any further comment until the official disciplinary decision is announced by end of July."
If found guilty PSG will likely face a partial stadium closure during their next UEFA-sanctioned match as punishment.
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