The Federal Fiscal Court (BFH) does not consider the solidarity surcharge in the form that has been in force since 2020 to be unconstitutional.
That was the verdict of the highest German tax court on Monday in Munich.
According to the Federal Fiscal Court, the federal government's income from the solos amounted to 11 billion euros.
If the levy were to be declared unconstitutional one day, the question would be whether the federal government would have to pay back its solidarity surcharges.
An elderly couple from Aschaffenburg complained.
With the support of the taxpayers' association, it wants to bring down the solos.
The lawsuit is based on two arguments: the solidarity surcharge was intended to finance the burdens of German unity, but this purpose has not been used since 2019.
At that time, the Solidarity Pact II expired, and since then there has been no special funding for the East German states.
In addition, the plaintiffs and their lawyers accuse the federal government of violating the principle of equality in the Basic Law, because only a small minority of taxpayers have to pay the tax, but not the vast majority.
With the law on the return of the solidarity compensation from 2019, the then grand coalition decided that only higher earners - the top ten percent of incomes - would have to pay the surcharge.
The remaining ninety percent of taxpayers should remain exempt.
According to the plaintiffs' lawyer, about 2.5 million people are still paying the solos.
Taxpayer President Reiner Holznagel said the process was an important stage.
The lawsuit was at least tacitly supported by Federal Finance Minister Christian Lindner (FDP), who wants to abolish the solos anyway.
The ministry originally joined the proceedings before the Federal Fiscal Court.
This is common in cases where the ministry rejects a claim.
Lindner had reversed that, however, and the Ministry of Finance is no longer involved in the solidarity process.