Between 2021 and 2023, Luxembourg's tax authorities reviewed 9,500 electronic tax declarations, resulting in nearly equal numbers of refunds and additional payments, according to Finance Minister Gilles Roth.

Submitting returns online is the fastest and easiest method, and an increasing number of people are now choosing to do so. However, even electronic returns are still subject to verification by tax officials, and these random checks can cover several years.

According to figures provided by Finance Minister Gilles Roth in response to a parliamentary question from MP André Bauler of the Democratic Party (DP), a total of 9,500 electronic tax declarations for the years 2021–2023 were reviewed in 2024. Of these, 3,902 cases (41%) resulted in refunds averaging €994, while 3,554 cases (37%) led to additional taxes owed to the Treasury, averaging €1,493. In 2,044 cases (around 22%), no financial adjustment was necessary.

Roth explained that such corrections may result from simple input errors, such as misplaced commas or points, or from missing income or deductions. He added that improvements to the digital tax assistant are planned to help reduce the number of errors and future corrections.

Roth emphasised that electronic filing speeds up processing, since assessments and payments, both refunds and additional taxes, are made immediately without waiting for a subsequent audit. However, he clarified that each return may still be subject to a manual review within five years, as permitted by tax law.