| Country | Action | Action Date | Effective Date |
|---|
| BELGIUM | Signature | 15/07/1957 | |
| BELGIUM | Ratification | 22/02/1960 | 22/02/1960 |
| FRANCE | Signature | 15/07/1957 | |
| FRANCE | Ratification | 22/02/1960 | 22/02/1960 |
| GERMANY FEDERAL REPUBLIC | Signature | 15/07/1957 | |
| GERMANY FEDERAL REPUBLIC | Ratification | 02/12/1965 | 02/12/1965 |
| GREECE | Accession | 20/05/1987 | 01/09/1987 |
| GREECE | Declaration | 20/05/1987 | |
| ITALY | Ratification | 22/02/1960 | 22/02/1960 |
| ITALY | Signature | 15/07/1960 | |
| LUXEMBOURG | Signature | 15/07/1957 | |
| LUXEMBOURG | Ratification | 22/02/1960 | 22/02/1960 |
| NETHERLANDS THE | Signature | 15/07/1957 | |
| NETHERLANDS THE | Ratification | 19/05/1960 | 19/05/1960 |
| PORTUGAL | Accession | 31/03/1987 | 01/09/1987 |
| UNITED KINGDOM | Accession | 30/08/1972 | 01/09/1972 |