| Country | Action | Action Date | Effective Date |
|---|---|---|---|
| CZECHOSLOVAKIA | Signature | 21/08/1931 | |
| FRANCE | Signature | 21/08/1931 | |
| ITALY | Signature | 21/08/1931 | |
| ROUMANIA | Signature | 21/08/1931 | |
| SWITZERLAND | Signature | 21/08/1931 | |
| SWITZERLAND | Ratification | 28/12/1931 | |
| UNITED KINGDOM | Signature | 21/08/1931 | |
| YUGOSLAVIA | Signature | 21/08/1931 |