FFO / Net debt under an S&P-style approximation can be estimated as:

**FFO ≈ cash flow from operations before working-capital changes − cash taxes paid + cash interest paid adjustment if needed**

Using the available cash-flow data, a practical S&P-style proxy is:
- Cash flows from operations before changes in working capital: **€1,202.0m**
- Less income taxes paid: **€165.9m**

So estimated **FFO**:
\[
1{,}202.0 - 165.9 = 1{,}036.1 \text{ million EUR}
\]

Next, estimate **net debt** as financial debt including lease liabilities minus cash and cash equivalents.

Debt components at 2022 year-end:
- Noncurrent financial liabilities: **€5,689.9m**
- Current financial liabilities: **€650.1m**
- Noncurrent lease liabilities: **€55.1m**
- Current lease liabilities: **€21.3m**

Gross debt:
\[
5{,}689.9 + 650.1 + 55.1 + 21.3 = 6{,}416.4 \text{ million EUR}
\]

Less cash and cash equivalents:
- Cash and cash equivalents: **€1,942.4m**

Net debt:
\[
6{,}416.4 - 1{,}942.4 = 4{,}474.0 \text{ million EUR}
\]

Therefore:
\[
\text{FFO / Net debt} = \frac{1{,}036.1}{4{,}474.0} = 0.2316 \approx 23.2\%
\]

<answer>23.2%</answer>