I. – Late filing or failure to file the declarations that must be filed in order to establish income tax, as well as inaccuracies or omissions noted in these declarations, which have the effect of reducing the tax owed by the taxpayer or increasing a claim to his benefit, give rise to the payment of an increase equal to 10% of the duties charged to the taxpayer or of the undue claim.
The increase is raised to 20% in the event of late filing within thirty days of formal notice.
II. – This increase is not applicable:
a) When the taxpayer has corrected his return spontaneously or within thirty days following a request from the administration;
b) Or when the increases provided for by b and c of 1 of article 1728, by article 1729 or by the a in l’article 1732.
III. – The increase provided for in I applies to the exclusion of that provided for in a of 1 of article 1728.