For many years Champollion’s progress was blocked because, like de Sacy and earlier scholars, he believed the hieroglyphs represented things, not sounds. Then, in 1822, he reversed his position. Some of Champollion’s rivals sug­gested that he had gotten the idea from Thomas Young’s Encyclopedia Britannica article. There the English scholar explained how the hiero­glyphs in Ptolemy’s name stood for sounds. Champollion hotly denied these suggestions, claiming that he had arrived at his new position entirely on his own. —The Riddle of the Rosetta Stone,
James Cross Giblin

How was Champollion’s early work similar to the work of de Sacy?

Both men thought that hieroglyphs stood for things rather than sounds.
Both men believed that hieroglyphs stood for sounds rather than things.
Both men used Akerblad’s demotic alphabet.
Both men discussed their ideas about the stone with Thomas Young.