Let’s reason step-by-step.

**1. Identify FFO (Funds From Operations)**  
FFO is typically calculated as:  
**FFO = Comparable EBITDA – Net financial expenses – Income taxes paid**

From the data:  
- Comparable EBITDA (2022): 2,436,000,000 EUR  
- Finance income/cost (net) (2022): –193,000,000 EUR  
- Income taxes paid (2022): –167,000,000 EUR (cash outflow shown as positive in tax paid line in cash flow, but here as a subtraction)  

So:  
FFO = 2,436,000,000 – 193,000,000 – 167,000,000  
FFO = 2,076,000,000 EUR  

**2. Identify Net Debt**  
Net debt = Interest-bearing liabilities – Liquid funds  

From the balance sheet:  
- Non-current financial liabilities (2023-01-01): 3,658,000,000 EUR  
- Current financial liabilities (2023-01-01): 4,127,000,000 EUR  
- Liquid funds (2023-01-01): 3,919,000,000 EUR  

Net debt = (3,658,000,000 + 4,127,000,000) – 3,919,000,000  
Net debt = 7,785,000,000 – 3,919,000,000  
Net debt = 3,866,000,000 EUR  

**3. FFO / Net Debt**  
FFO / Net Debt = 2,076,000,000 / 3,866,000,000 ≈ 0.537  

<answer>0.537</answer>