I do multi-lingual
SEO for clients.
The search engines read the words on your pages. "J'ai perdu mon nounourse" are not the same words as "I lost my teddy bear." You are safe.
As for two different TLDs with the same content, that is duplicate content. However, your positions will not be hurt unless Google et al. think you are trying to game them by claiming multiple spots for the same search terms using different domains. At worst, the results from all but one site will be filtered out.
The smart thing to do is to change the wording enough, which should not be hard, given that a .ca site should mention Canada and/or locations in Canada and contain lots of words ending in our that the .com site probably would not have.
I hope that helps.