Health insurance contributions are counted as pension expenses and can be deducted from taxes. If the fund reimburses contributions, you usually have to declare the repayments in your tax return.
Things are different with bonus payments - but when is proof required? The Federal Ministry of Finance has now made it clear that bonus payments of up to 150 euros are considered a premium refund. This means: Taxpayers who receive more than 150 euros per year as a bonus reimbursed from their health insurance company for health-conscious behavior must prove to the tax office that these are not premium refunds.