You are correct for the first number (181k to 100k), but not the second one, as the income tax is calculated by brackets defined in adavance[1]. A single person with no family winning 100k would have to pay 23k, leaving them with 77k. This is more than twice the average in France[2] and nearly thrice the median salary [3].
[1] : https://www.service-public.fr/particuliers/vosdroits/F1419 [2] : https://www.insee.fr/fr/statistiques/serie/010752333 [3] : https://www.insee.fr/fr/statistiques/6436313#titre-bloc-9