To estimate the FFO (Funds From Operations) / Net Debt ratio for Bouygues for the year 2022 according to S&P methodology, we first identify the relevant components from the provided data.

1.  **FFO Calculation**: According to standard S&P methodology, FFO is generally calculated as "Cash Flow from Operations" adjusted for changes in working capital and certain non-cash items.
    *   Cash Flows from Operating Activities (2022): 2,978,000,000 EUR
    *   Adjustment: In S&P methodology, the "Change in working capital" (which is an inflow/outflow impacting cash from operations) is added back to approximate cash generated from core activities.
    *   Change in Working Capital (2022): 606,000,000 EUR (as a positive inflow in the provided data).
    *   Standardized FFO calculation: Operating Cash Flow - Change in Working Capital.
    *   FFO = 2,978,000,000 EUR - 606,000,000 EUR = 2,372,000,000 EUR.

2.  **Net Debt**:
    *   The provided data explicitly lists "Net Debt" for 2023-01-01 (representing the end of 2022) as 7,440,000,000 EUR.

3.  **Calculation**:
    *   Ratio = FFO / Net Debt
    *   Ratio = 2,372,000,000 / 7,440,000,000
    *   Ratio ≈ 0.3188

(Note: The data provided covers the period up to the beginning of 2023, which corresponds to the fiscal year-end 2022 report).

<answer>0.3188</answer>