To estimate the Net Debt / EBITDA ratio following S&P methodology, I need to calculate two things from the provided data:  
1. **EBITDA** (adjusted, as S&P would typically use)  
2. **Net Debt** (total debt minus cash and cash equivalents, with adjustments for certain items S&P includes as debt)  

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### Step 1 – EBITDA (Approximate)
We use:  
**Operating income before share of net income of equity-accounted entities + Depreciation, amortization, provisions, impairment (from cash flow statement)**  

From the data:
- Operating income before share of net income/loss of equity accounted entities (2022-01-01 to 2023-01-01): 2,206,300,000 EUR
- Operating depreciation, amortization, provisions and impairment losses (same period): 3,178,600,000 EUR

EBITDA ≈ 2,206.3M + 3,178.6M  
= **5,384,900,000 EUR**

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### Step 2 – Net Debt (S&P style)
S&P generally includes:
- Short-term and long-term borrowings
- Lease liabilities
- Deeply subordinated securities (often treated as debt if not 100% equity credit)
- Minus cash and cash equivalents

From the balance sheet (2023-01-01):
- Noncurrent financial liabilities (excluding concession): 19,692,100,000
- Noncurrent lease liabilities: 1,656,200,000
- Noncurrent concession liabilities: 1,680,500,000
- Current financial liabilities (excluding concession): 6,521,400,000
- Current lease liabilities: 496,500,000
- Current concession liabilities: 243,200,000
- Deeply subordinated securities (Titres Super Subordonnés): 3,496,300,000
- Bank overdrafts: 213,600,000
- Cash and cash equivalents: 9,012,200,000

**Total gross debt** =  
19,692.1M + 1,656.2M + 1,680.5M + 6,521.4M + 496.5M + 243.2M + 3,496.3M + 213.6M  
= **33,999,800,000 EUR**

**Net debt** = 33,999.8M - 9,012.2M  
= **24,987,600,000 EUR**

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### Step 3 – Net Debt/EBITDA
Ratio = 24,987.6M / 5,384.9M  
≈ **4.64**

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<answer>4.64</answer>