To determine the S&P credit trend for ENGIE from 2021 to 2022, we follow the S&P methodology, incorporating the specific guidelines for the Regulated Utilities and Unregulated Power and Gas sectors where appropriate.

**Step 1: Identify the Industry and Guidelines**
ENGIE operates primarily within the Regulated Utilities and Unregulated Power and Gas sectors. While standard corporate formulas for EBITDA, FFO, and Adjusted Debt apply, specific attention is given to power-purchase agreements, mark-to-market (MTM) derivatives variations, and asset retirement obligations (nuclear and environmental provisions) which are heavily represented in their financials.

**Step 2 & 3: Estimate 2021 Adjusted EBITDA and FFO**
Under S&P guidelines, we reverse non-cash items (like MTM derivative gains/losses) and start with cash flow measures to get a proxy for core operating cash generation.
- **Cash Flows from Operations before Changes in Working Capital (2021):** €9,807M
- **Cash Interest Paid:** Interest paid was classified under financing activities, so it was not deducted from operating cash flows. The cash interest paid was €719M.
- **FFO (2021) =** CFO before WC - Cash Interest Paid = 9,807 - 719 = **€9,088M**
- **Cash Taxes Paid:** €603M (already deducted in operating cash flow).
- **Adjusted EBITDA (2021) =** FFO + Cash Interest + Cash Taxes = 9,088 + 719 + 603 = **€10,410M**

**Step 4: Estimate 2021 Adjusted Debt**
- **Reported Borrowings (Current + Long-term):** €10,590M + €30,458M = €41,048M
- **Less: Cash and Cash Equivalents:** -€13,890M
- **Plus: 50% of Hybrid Debt (Deeply Subordinated Perpetual Notes):** 50% of €3,767M = €1,883M
- **Plus: Net Asset Retirement / Pension Provisions (Total Provisions minus dedicated Non-current Financial Assets):** (€23,394M + €2,066M) - €10,949M = €14,511M
- **Adjusted Debt (2021) =** 41,048 - 13,890 + 1,883 + 14,511 = **€43,552M**

**Step 5 & 6: 2021 Ratios**
- **Adjusted Debt / Adjusted EBITDA =** 43,552 / 10,410 = **4.18x**
- **FFO / Adjusted Debt =** 9,088 / 43,552 = **0.2087 (20.87%)**

**Step 7 & 8: Estimate 2022 Adjusted EBITDA and FFO**
During the 2022 European energy crisis, elevated prices and market volatility created massive accounting MTM distortions, but underlying cash generation was robust. 
- **Cash Flows from Operations before Changes in Working Capital (2022):** €12,415M
- **Cash Interest Paid:** €822M
- **FFO (2022) =** 12,415 - 822 = **€11,593M**
- **Cash Taxes Paid:** €1,504M
- **Adjusted EBITDA (2022) =** 11,593 + 822 + 1,504 = **€13,919M**

**Step 9: Estimate 2022 Adjusted Debt**
- **Reported Borrowings (Current + Long-term):** €12,508M + €28,083M = €40,591M
- **Less: Cash and Cash Equivalents:** -€15,570M
- **Plus: 50% of Hybrid Debt:** 50% of €3,393M = €1,696M
- **Plus: Net Asset Retirement / Pension Provisions:** (€24,663M + €2,365M) - €10,599M = €16,429M
- **Adjusted Debt (2022) =** 40,591 - 15,570 + 1,696 + 16,429 = **€43,146M**

**Step 10 & 11: 2022 Ratios**
- **Adjusted Debt / Adjusted EBITDA =** 43,146 / 13,919 = **3.10x**
- **FFO / Adjusted Debt =** 11,593 / 43,146 = **0.2687 (26.87%)**

**Step 12: Classify the Year-on-Year Credit Trend**
- **Signal 1: Leverage:** The Adjusted Debt / Adjusted EBITDA ratio went from 4.18x to 3.10x, representing a change of **-1.08x**. Since this is ≤ -0.2x, this signal is **Improving**.
- **Signal 2: Cash-Flow Coverage:** The FFO / Adjusted Debt ratio went from 0.2087 to 0.2687, representing a change of **+0.0600 (+6.00 percentage points)**. Since this is ≥ +0.03, this signal is **Improving**.

Both signals strongly agree, highlighting debt stability coupled with a massive boost in fundamental cash flows.

<answer>Improving</answer>