French être is from PIE h₁ésti https://en.wiktionary.org/wiki/Reconstruction:Proto-Indo-Eur... which also gave rise to Marathi आथि (āthi). Marathi असणे (asṇe) https://en.wiktionary.org/wiki/%E0%A4%85%E0%A4%B8%E0%A4%A3%E... appears unrelated. (But might be cognate to English at home?)

Not all similarities between mondern languages are inherited, coincidences do happen.