A police spokesman says the vandalism at the Saint-Roch cemetery occurred over several days in mid-August.
Martin Carrier says that, for now, no link has been established with the current Quebec election campaign or Charest's Liberal party.
Charest is seeking re-election in the Sherbrooke riding and one recent poll had him badly trailing the Parti Quebecois candidate.
Police say seven tombstones in the cemetery were damaged, crosses on the stone markers were broken and flowers were overturned.
They are seeking public assistance to find those responsible.
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