A priority claim is an allowance based on Article 4 of the Paris Convention for the Protection of Industrial Property. It enables you as the owner of a filed trademark to file subsequent trademark applications in any of the Convention’s signatory countries using the effective date of your first application as long as you file the subsequent applications within six months of your original trademark application. That means if you apply for a trademark in Canada, five months later, you can apply for a trademark in France using the effective date of your Canadian application.
We strongly recommend that you submit your additional applications as soon as possible after your base application. Many countries have strict requirements regarding the type of documentation required in order to claim priority (sometimes including legalization and translation of the original application).