The Standards in Public Office Commission has found that a former member of Donegal County Council and former board member of Údarás na Gaeltachta, Pádraig Doherty, contravened sections of the Local Govt Act, 2001.
The Commission's report relates to an investigation into double claims made by Mr Doherty.
It covered claims by the independent councillor from Gaoth Dobhair in for travel and subsistence expenses in 2007 and 2008.
A hearing was held in the SIPO offices in Dublin on 12 May.
It found that Mr Doherty contravened sections 168 and 169 of the Local Govt Act, acting recklessly and not in good faith when he made claims to both the Council and Údarás for conferences and meetings he attended in Dundalk, Dungarvan and Na Forbacha, Galway.
The report stated that these were 'serious matters'.
A barrister for Mr Doherty stated at the SIPO hearing that his client had made errors in relation to dates on the claims forms and had later rectified these errors.
SIPO has sent its report to Donegal County Council, as well as Minister for Public Expenditure Brendan Howlin and Minister for the Environment Phil Hogan.