Income tax: Here, the tax office takes a very close look at the 2025 tax return

Nine years ago, it was an important tax innovation: the obligation to retain documents replaced the obligation to submit documents. This means that anyone who submits their tax return to the tax office generally no longer has to attach or upload documents such as tax certificates, cash receipts or transfer proofs. In principle, it is sufficient to keep the documents.

However, there are some constellations in which the tax officials want to know exactly and will ask with great probability. If you send your documents directly with your tax return in such cases, you speed up the processing and get your tax refund faster. The following overview shows 16 cases in which this makes sense.

Significant facts instead of audit fields

In North Rhine-Westphalia, there was a peculiarity for a long time: the tax administration annually published so-called audit fields. They showed which areas the tax offices in the most populous federal state examined particularly closely in the respective year. This was intended to facilitate the work of tax consultants and tax officials. This is because consultants could send documents directly with the tax return for the audit fields, and tax officials did not have to request them first.

The tax administration in NRW no longer publishes its audit fields, but documents and proofs should still be submitted directly with the tax return in the case of "special" facts. The tax administration calls a tax fact special if it is new, first-time or one-time, represents an extraordinary (business) incident, changes significantly compared to the previous year or has a significant tax impact.

What exactly is meant by this can be seen from a list of "significant facts". It largely corresponds to a list of the Bavarian tax administration.

It is recommended to submit documents immediately for private individuals in the following 16 constellations:

New care contributions

There are so-called professional pension institutions for some professional groups - for example, for doctors, architects, lawyers, psychotherapists and engineers. They are an alternative to statutory pension insurance. For employees, the employer usually pays the contributions to the pension institutions. Anyone who pays their own contributions to professional pension institutions for the first time should provide proof.

Jana Bauer, Managing Director of the Federal Association of Wage Tax Assistance Associations (BVL), also recommends this to taxpayers who make voluntary contributions (additional payments) to statutory pension insurance. "So far, only the regular contributions to old-age provision are transmitted electronically to the tax administration," says Bauer.

Significant donations

Donations to charitable organizations can be claimed as special expenses on the tax return. For amounts up to 300 euros, a booking confirmation from the bank - such as a bank statement - or a cash deposit slip is sufficient as proof. For higher amounts, a donation certificate from the donation organization is necessary. In the case of "significant donations", the NRW tax administration recommends submitting a document.

The tax administration does not specify a specific amount. Whether a donation is classified as significant depends on the individual case, according to the North Rhine-Westphalia Higher Tax Office. Both the absolute amount and the ratio of the donation to the taxable income can play a role.

Maintenance payments

Tax offices see a high risk of abuse in maintenance payments. Since the 2025 tax year, such payments can only be claimed for tax purposes if they are transferred to a bank account. The tax office also always requires proof that the supported person is in need. "Typical maintenance payments include when parents support their children - for whom they no longer receive child benefit - financially during their studies," says tax expert Bauer.

The requirement is that the supported child has no own income and at most a small fortune. If the child earns more than 624 euros per year, the income is offset against the maintenance payments. If persons are supported abroad, maintenance declarations must be completed and the information confirmed by local authorities at the supported person's place of residence.

The tax administration provides forms in various languages for this purpose, which should be attached to the tax return.

Application for unlimited tax liability

Anyone who has no residence in Germany is generally not liable for taxes here. What initially sounds advantageous can have major disadvantages if a person receives income in Germany. This is because anyone who is not unlimitedly liable for taxes here does not enjoy tax allowances such as the basic allowance. Anyone who submits an application for unlimited tax liability in accordance with Section 1 (3) of the Income Tax Act should also submit documents for this, according to the NRW tax administration.

Unlimited tax liability can be granted if a person has no residence in Germany but receives at least 90 percent of their income here or if their foreign income does not exceed the basic allowance.

Reduced taxation of severance pay

Anyone who received severance pay, compensation or remuneration for several years of service in the past year is likely to be in a hurry with their tax return. This is because the tax advantage for such payments has been abolished by the employer in the case of wage tax since 2025. Instead, those affected must now apply for the more favorable taxation via their tax return.

The principle remains the same: thanks to the so-called one-fifth regulation, the one-off payment is treated for tax purposes as if it were distributed over five years.