Fontana's fingering is almost certainly identical with the indication in FED, stemming from a lesson with Chopin. In that copy, apart from the evident digit '2,' written twice in a way typical of FED, first by Chopin, then by Madame Dubois, there is a visible delicate line next to the a1 quaver. The mark could be interpreted as a digit '1,' yet it is uncertain, hence in the main text, we give only the '2' described above.
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issues: Annotations in teaching copies, EE revisions, Annotations in FED
notation: Fingering