**Step 1: Identify the relevant industry**  
VINCI operates primarily in transportation infrastructure (concessions, toll roads, airports). While it also has construction activities, the provided methodology for “Transportation Infrastructure” is most applicable.  

**Step 2: Estimate 2021 Adjusted_EBITDA**  
- Start with reported profit from operating activities (2021): €4,438 million.  
- Add back depreciation and amortisation (2021): €3,219 million.  
- EBITDA = €4,438 M + €3,219 M = €7,657 million.  
- Adjust for non‑recurring items (from cash‑flow adjustments):  
  - Gains on disposal of non‑current assets: €27 M (gain, subtract).  
  - Fair‑value gains: €54 M (gain, subtract).  
  - Impairment loss: €206 M (loss, add).  
  - Net adjustment = +€206 M – €27 M – €54 M = +€125 million.  
- **Adjusted_EBITDA (2021)** = €7,657 M + €125 M = **€7,782 million**.  

**Step 3: Estimate 2021 FFO**  
- FFO = Adjusted_EBITDA – cash interest – cash taxes.  
- Cash interest paid (interest paid and interest received, 2021): €557 million.  
- Cash taxes paid (income taxes paid, 2021): €1,213 million.  
- **FFO (2021)** = €7,782 M – €557 M – €1,213 M = **€6,012 million**.  

**Step 4: Estimate 2021 Adjusted_Debt**  
- Total reported debt (2021) = non‑current bonds (€22,212 M) + other non‑current borrowings (€2,757 M) + short‑term borrowings (€5,769 M) + non‑current lease liabilities (€1,574 M) + current lease liabilities (€524 M) = **€32,836 million**.  
- Eligible cash (2021) = cash and cash equivalents (€11,065 M) + current cash‑management financial assets (€200 M) + other current financial assets (€100 M) = **€11,365 million**.  
- **Adjusted_Debt (2021)** = €32,836 M – €11,365 M = **€21,471 million**.  

**Step 5: Calculate 2021 ratio**  
- Adjusted_Debt / Adjusted_EBITDA (2021) = €21,471 M / €7,782 M ≈ **2.76×**.  

**Step 6: Calculate 2021 FFO / Adjusted_Debt**  
- FFO / Adjusted_Debt (2021) = €6,012 M / €21,471 M ≈ **0.280**.  

**Step 7: Estimate 2022 Adjusted_EBITDA**  
- Start with reported profit from operating activities (2022): €6,489 million.  
- Add back depreciation and amortisation (2022): €3,613 million.  
- EBITDA = €6,489 M + €3,613 M = €10,102 million.  
- Adjust for non‑recurring items:  
  - Gains on disposal: €68 M (subtract).  
  - Fair‑value gains: €236 M (subtract).  
  - Net adjustment = –€68 M – €236 M = –€304 million.  
- **Adjusted_EBITDA (2022)** = €10,102 M – €304 M = **€9,798 million**.  

**Step 8: Estimate 2022 FFO**  
- Cash interest paid (2022): €563 million.  
- Cash taxes paid (2022): €1,603 million.  
- **FFO (2022)** = €9,798 M – €563 M – €1,603 M = **€7,632 million**.  

**Step 9: Estimate 2022 Adjusted_Debt**  
- Total reported debt (2022) = non‑current bonds (€20,425 M) + other non‑current borrowings (€3,205 M) + short‑term borrowings (€6,368 M) + non‑current lease liabilities (€1,580 M) + current lease liabilities (€522 M) = **€32,100 million**.  
- Eligible cash (2022) = cash and cash equivalents (€12,578 M) + current cash‑management financial assets (€755 M) + other current financial assets (€84 M) = **€13,417 million**.  
- **Adjusted_Debt (2022)** = €32,100 M – €13,417 M = **€18,683 million**.  

**Step 10: Calculate 2022 ratio**  
- Adjusted_Debt / Adjusted_EBITDA (2022) = €18,683 M / €9,798 M ≈ **1.91×**.  

**Step 11: Calculate 2022 FFO / Adjusted_Debt**  
- FFO / Adjusted_Debt (2022) = €7,632 M / €18,683 M ≈ **0.409**.  

**Step 12: Classify the credit trend**  
- **Signal 1 (Leverage):** Change = 1.91 – 2.76 = –0.85×. Since ≤ –0.2×, this signals **Improving**.  
- **Signal 2 (Cash‑flow coverage):** Change = 0.409 – 0.280 = +0.129. Since ≥ +0.03, this signals **Improving**.  
- Both signals agree on **Improving**.  

**Conclusion:** The credit trend from 2021 to 2022 is **Improving**.

<answer>Improving</answer>