FFO (Funds From Operations) can be estimated from operating cash-flow data before working-capital movements.

Using the provided cash-flow facts:

- Cash flow after cost of net debt, lease interest and income taxes paid: €3,324 million
- Adjustments for cost of net debt and interest expense on lease obligations: €260 million
- Income taxes paid: €518 million

So estimated FFO before working-capital changes:

\[
FFO = 3{,}324 + 260 + 518 = 4{,}102 \text{ million EUR}
\]

Net debt at 2022 year-end:

\[
Net\ Debt = 7{,}440 \text{ million EUR}
\]

Therefore:

\[
FFO / Net\ Debt = \frac{4{,}102}{7{,}440} = 0.5513
\]

As a percentage:

\[
0.5513 \times 100 = 55.1\%
\]

<answer>55.1%</answer>