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RELATED PARTIES - Narrative (Details) - EUR (€) € in Millions |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 28, 2018 | Dec. 31, 2020 | May 13, 2020 | Dec. 31, 2019
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings |  | € 2,391 |  | € 2,361
Secured French PGE French Facility (due 206) |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings |  | 180 |  | 0
Secured French PGE French Facility (due 206) | French Government |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings |  |  | € 180 |
Percentage of borrowings guaranteed |  |  | 80.00% |
Secured French PGE French Facility (due 206) | French Government | BPI France |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings |  |  | € 30 |
Unsecured Revolving Credit Facility (due 2021) |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings |  | 0 |  | € 0
Unsecured Revolving Credit Facility (due 2021) | BPI France |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Term of credit facility | 3 years |  |  |
Borrowing capacity | € 10 | € 3 |  |

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