| Country | Action | Action Date | Effective Date |
|---|---|---|---|
| BELGIUM | Accession | 07/01/1929 | |
| FRANCE | Signature | 25/07/1928 | |
| FRANCE | Ratification | 14/09/1928 | |
| ITALY | Signature | 25/07/1928 | |
| ITALY | Ratification | 14/09/1928 | |
| NETHERLANDS THE | Accession | 12/06/1929 | |
| PORTUGAL | Accession | 29/01/1929 | |
| SPAIN | Signature | 25/07/1928 | |
| SPAIN | Ratification | 14/09/1928 | |
| SWEDEN | Accession | 19/10/1928 | |
| UNITED KINGDOM | Signature | 25/07/1928 | |
| UNITED KINGDOM | Ratification | 14/09/1928 |