To estimate S&P's credit trend for BOUYGUES from 2021 to 2022, we apply the general corporate baseline formulas since the company's diversified operations (which include construction, telecoms, and media) do not strictly fall under the specific single-industry methodologies provided.

**Step 1. Identify the relevant industry**
General Corporate Baseline applies.

**Step 2. Estimate the 2021 Adjusted EBITDA**
Adjusted EBITDA is typically estimated as Operating Profit + Depreciation and Amortization.
- Profit Loss From Operating Activities (2021): €1,733M 
- Depreciation and Amortisation Expense (2021): €2,065M
*Adjusted EBITDA (2021)* = 1,733 + 2,065 = €3,798M
*(Note: Adding Right-of-Use Depreciation of €353M would raise it to €4,151M, but does not alter the trend.)*

**Step 3. Estimate the 2021 FFO (Funds From Operations)**
FFO = Adjusted EBITDA - Cash Interest - Cash Taxes
- Cash Interest Paid (2021): €207M
- Cash Taxes Paid (2021): €397M
*FFO (2021)* = 3,798 - 207 - 397 = €3,194M

**Step 4. Estimate the 2021 Adjusted Debt**
Adjusted Debt = Total Borrowings + Lease Liabilities - Cash & Equivalents
- Long-term Borrowings: €5,805M
- Short-term Borrowings/Overdrafts: €1,324M + €351M = €1,675M
- Lease Liabilities (Current + Non-current): €362M + €1,473M = €1,835M
- Cash and Cash Equivalents: €6,501M
*Adjusted Debt (2021)* = 5,805 + 1,675 + 1,835 - 6,501 = €2,814M

**Step 5. Calculate the 2021 Adjusted Debt / Adjusted EBITDA**
*Leverage (2021)* = 2,814 / 3,798 = **0.74x**

**Step 6. Calculate the 2021 FFO / Adjusted Debt**
*FFO to Debt (2021)* = 3,194 / 2,814 = **1.135 (or 113.5%)**

**Step 7. Estimate the 2022 Adjusted EBITDA**
- Profit Loss From Operating Activities (2022): €1,872M
- Depreciation and Amortisation Expense (2022): €2,228M
*Adjusted EBITDA (2022)* = 1,872 + 2,228 = €4,100M

**Step 8. Estimate the 2022 FFO**
- Cash Interest Paid (2022): €260M
- Cash Taxes Paid (2022): €518M
*FFO (2022)* = 4,100 - 260 - 518 = €3,322M

**Step 9. Estimate the 2022 Adjusted Debt**
Long-term borrowings significantly jumped due to M&A activities (acquisition of Equans).
- Long-term Borrowings: €11,586M
- Short-term Borrowings/Overdrafts: €1,361M + €418M = €1,779M
- Lease Liabilities (Current + Non-current): €498M + €2,107M = €2,605M
- Cash and Cash Equivalents: €5,736M
*Adjusted Debt (2022)* = 11,586 + 1,779 + 2,605 - 5,736 = €10,234M

**Step 10. Calculate the 2022 Adjusted Debt / Adjusted EBITDA**
*Leverage (2022)* = 10,234 / 4,100 = **2.50x**

**Step 11. Calculate the 2022 FFO / Adjusted Debt**
*FFO to Debt (2022)* = 3,322 / 10,234 = **0.325 (or 32.5%)**

**Step 12. Classify the year-on-year credit trend**
- **Signal 1 (Leverage):** 2.50x - 0.74x = +1.76x. This is an increase ≥ +0.2x, firmly indicating **Deteriorating**.
- **Signal 2 (Cash-flow coverage):** 0.325 - 1.135 = -0.810 (an 81 percentage point drop). This is a decrease ≤ -0.03, firmly indicating **Deteriorating**.

Both signals strongly agree, primarily driven by a massive increase in debt from external financing to support strategic acquisitions, resulting in a heavily suppressed cash flow coverage and higher absolute leverage.

<answer>Deteriorating</answer>