| Country | Action | Action Date | Effective Date |
|---|
| AUSTRIA | Signature | 21/05/1931 | |
| BELGIUM | Signature | 21/05/1931 | |
| BULGARIA | Signature | 21/05/1931 | |
| CZECHOSLOVAKIA | Signature | 21/05/1931 | |
| DENMARK | Signature | 21/05/1931 | |
| DENMARK | Reservation | 21/05/1931 | |
| ESTONIA | Signature | 21/05/1931 | |
| FINLAND | Signature | 21/05/1931 | |
| FRANCE | Signature | 21/05/1931 | |
| GERMANY | Signature | 21/05/1931 | |
| GREECE | Signature | 21/05/1931 | |
| GREECE | Ratification | 31/08/1931 | |
| HUNGARY | Signature | 21/05/1931 | |
| ITALY | Signature | 21/05/1931 | |
| LATVIA | Signature | 21/05/1931 | |
| LATVIA | Ratification | 28/09/1931 | |
| LITHUANIA | Signature | 21/05/1931 | |
| LUXEMBOURG | Signature | 21/05/1931 | |
| NETHERLANDS THE | Signature | 21/05/1931 | |
| POLAND | Signature | 21/05/1931 | |
| POLAND | Ratification | 22/04/1932 | |
| PORTUGAL | Signature | 21/05/1931 | |
| ROUMANIA | Signature | 21/05/1931 | |
| ROUMANIA | Ratification | 04/02/1932 | |
| SPAIN | Signature | 21/05/1931 | |
| SWEDEN | Reservation | 21/05/1931 | |
| SWEDEN | Signature | 17/09/1931 | |
| SWITZERLAND | Signature | 21/05/1931 | |
| SWITZERLAND | Ratification | 31/12/1931 | |
| UNITED KINGDOM | Signature | 21/05/1931 | |
| YUGOSLAVIA | Signature | 21/05/1931 | |
| YUGOSLAVIA | Ratification | 16/01/1934 | |