The suggestion I've seen is that key countries will put a price on carbon, and then add tariffs to imports from countries that lack a carbon price. That at least goes some way to removing the economic disadvantage.
There is unfortunately still a lot of scope to game such a system.
A country can sign up to the carbon pricing scheme, but then subsidise disadvantaged industries by almost the same amount as the carbon taxes they pay. See the EU carbon trading scheme for example - companies are given (for free) credits representing the carbon they emitted in past years.
A multi-country carbon taxation scheme gives every country a strong incentive to either collect the tax badly on their own companies, or make policies to effectively reimburse companies the tax collected.
It's probably still the best approach despite this shortcoming.
