For international companies, you will want to hire an accounting firm which has offices in both/all of the nations in which you will be operating.
There is a reason that accountants and tax lawyers dither more about the tax issues than lawyers do about other issues. (Tax lawyers will be lumped in with accountants hereafter because tax law is generally considered the practice of accounting in the US.) Under the laws of most nations, accountants can go to jail and be made to pay potentially unlimited penalties if they give bad tax advice, in addition to malpractice liability. Lawyers generally only have to worry about malpractice liability. Accountants generally face more risk than lawyers, and correspondingly spend more time mitigating that risk than lawyers do.
There is a reason that accountants and tax lawyers dither more about the tax issues than lawyers do about other issues. (Tax lawyers will be lumped in with accountants hereafter because tax law is generally considered the practice of accounting in the US.) Under the laws of most nations, accountants can go to jail and be made to pay potentially unlimited penalties if they give bad tax advice, in addition to malpractice liability. Lawyers generally only have to worry about malpractice liability. Accountants generally face more risk than lawyers, and correspondingly spend more time mitigating that risk than lawyers do.