The lawyers above have provided some great answers. My office dealt with this same issue (in France nonetheless) not too long ago. I'll add a little bit of practical advice based on our experience with the issue.
Georgia probate law does not require that an heir be in Georgia, or even in the United States in order to consent to a probate petition, or participate in probating an estate. All that Georgia probate law requires is that the signature of the person signing the consent be notarized. As a result, legally, there is no problem with having someone in a foreign county consent to a probate petition.
As a practical matter, however, there can be some interesting challenges. The practical problem we faced was that we could not find a French notary that was willing notarize the document unless it was in French. Unfortunately, if the consent were translated to French and signed, then the local probate court would not acept it because it was not in English. The only practical solution to this type of delimma is to have the person located in the foreign county go to the local U.S. Embassy or Consulate to have the document notarized and sent back to the U.S.
Based on that experience, our office recommends that our clients have foreign heirs go to the U.S Embassy or Consulate first to save time an energy.
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You may be able to find a notary at the US Embassy. Otherwise, the court will probably accept an apostile, which is a form of verification.
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France, as a Civil Law country, has officials called "notaires" who can perform the authenication service required for the acknowledgement of service and assent to probate. A notary in a Civil Law country is a higher status official than our notaries, and your sister should expect to pay a fee for authentication services. My colleague has also pointed out that the U.S. Embassy can perform that service as well.
I agree with the other attorneys re the use of the US embassy. I am not a GA attorney but we have similar forms in PA and NJ and usually they have one form if it is notarized before the Probate court and one if it is notarized elsewhere.
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The US embassy or consulate will notarize papers for a minimal fee. France also has notaries, which generally charge more than American ones but have a similar seal. Those are fine as well.
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I agree with the other responses about who can notarize your sister's signature. I just wanted to also point out that the form indicates that either the clerk of court OR a notary can notarize the heirs' signatures - not just that the court has to do it.
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