To estimate the Net Debt / EBITDA ratio for Bouygues for 2022 according to the S&P methodology, we first determine the components:

1.  **Net Debt (2022):** The provided report explicitly states the "Net Debt" at the end of 2022 (2022-01-01 equivalent to the start of 2023) is **941,000,000 EUR**.

2.  **EBITDA Calculation (2022):**
    S&P methodology generally defines EBITDA as Operating Profit + Depreciation and Amortisation + Impairment/Provisions adjustments.
    *   **Profit from Operating Activities (2022):** 1,733,000,000 EUR
    *   **Depreciation and Amortisation Expense:** 2,065,000,000 EUR
    *   **Depreciation of Right-of-Use Assets:** 353,000,000 EUR
    *   **Provisions/Impairment (Net expense):** 405,000,000 EUR
    *   *Calculation:* 1,733,000,000 + 2,065,000,000 + 353,000,000 + 405,000,000 = **4,556,000,000 EUR**.

    *(Note: S&P sometimes excludes non-recurring items or adjusts for specific leasing components, but using the provided figures for the 2021-2022 period relevant to the 2022 fiscal year results in this EBITDA estimate.)*

3.  **Ratio Calculation:**
    Net Debt / EBITDA = 941,000,000 / 4,556,000,000 ≈ 0.2065

Rounding to a standard financial representation:

<answer>0.21</answer>