Question juridique clé
Whether CHF 9,093 in flat expenses could be added back as taxable income despite long-standing administrative practice
Solution extraite
The add-back was unlawful because the authority applied a de facto retroactive change in practice contrary to good faith and legal certainty.
Motifs extraits
A long-standing practice of more than 20 years had allowed the taxpayer flat expense compensation. The authority could not, after the tax year had ended, require proof that had not previously been needed and thereby change practice with retroactive effect.