| Country | Action | Action Date | Effective Date |
|---|
| AUSTRIA | Signature | 18/06/1955 | |
| BELGIUM | Signature | 18/06/1955 | |
| BULGARIA | Signature | 18/06/1955 | |
| CZECHOSLOVAKIA | Signature | 18/06/1955 | |
| DENMARK | Signature | 18/06/1955 | |
| FINLAND | Signature | 27/12/1955 | |
| FRANCE | Signature | 18/06/1955 | |
| GREECE | Signature | 18/06/1955 | |
| HUNGARY | Signature | 18/06/1955 | |
| ITALY | Signature | 18/06/1955 | |
| LIECHTENSTEIN | Signature | 07/09/1955 | |
| LUXEMBOURG | Signature | 18/06/1955 | |
| NETHERLANDS THE | Signature | 18/06/1955 | |
| NORWAY | Signature | 23/09/1955 | |
| POLAND | Signature | 18/06/1955 | |
| PORTUGAL | Signature | 18/06/1955 | |
| ROUMANIA | Signature | 18/06/1955 | |
| SPAIN | Signature | 18/06/1955 | |
| SWEDEN | Signature | 18/06/1955 | |
| SWITZERLAND | Signature | 18/06/1955 | |
| TURKEY | Signature | 27/12/1955 | |
| UNITED KINGDOM | Signature | 18/06/1955 | |
| YUGOSLAVIA | Signature | 18/06/1955 | |