Step 1 — Relevant industry  
Bouygues is a diversified industrial group mainly active in construction, telecoms, media, and infrastructure-related activities. It does not fit cleanly into the provided industry methodologies for regulated utilities, E&P, unregulated power and gas, or transportation infrastructure. Therefore, I apply the general corporate baseline approach.

Step 2 — Estimate Adjusted Debt  

Use year-end 2022 balance sheet values at 2023-01-01.

Reported financial debt:
- Long-term borrowings: €11,586m
- Current borrowings and current portion of noncurrent borrowings: €1,361m
- Current overdrafts and short-term bank borrowings: €418m
- Other current financial liabilities: €13m

Reported debt before leases:
= 11,586 + 1,361 + 418 + 13  
= €13,378m

Lease liabilities:
- Noncurrent lease liabilities: €2,107m
- Current lease liabilities: €498m

Total leases:
= 2,107 + 498  
= €2,605m

Gross debt including leases:
= 13,378 + 2,605  
= €15,983m

Eligible cash:
- Cash and cash equivalents: €5,736m

Adjusted Debt:
= 15,983 - 5,736  
= €10,247m

Step 3 — Estimate Adjusted EBITDA  

Reconstruct EBITDA from operating profit.

Reported operating profit:
- Profit from operating activities: €1,872m

Add depreciation and amortization:
- Depreciation and amortisation expense: €2,228m

Add right-of-use asset depreciation:
- Depreciation right-of-use assets: €446m

EBITDA before nonrecurring adjustment:
= 1,872 + 2,228 + 446  
= €4,546m

Nonrecurring operating items:
- Other operating income nonrecurring: €93m
- Other operating expense nonrecurring: €183m

Net nonrecurring loss:
= 183 - 93  
= €90m

Add back net nonrecurring loss:
Adjusted EBITDA:
= 4,546 + 90  
= €4,636m

Step 4 — Adjusted Debt / Adjusted EBITDA  

Adjusted Debt / Adjusted EBITDA:
= 10,247 / 4,636  
= 2.2103

Rounded to two decimals:
= 2.21

<answer>2.21</answer>