Hi Odile,

Thank you for contacting Mearto with your appraisal inquiry.
The values listed online are retail and there's no transparency between what the buyer asks for and what they'll actually sell the painting for. The values Mearto provides are based on auction results, rather than gallery prices, and Polt's works usually sell for less than $500 at auction.
Based on the photos and information provided, and subject to examination, this is:

H. Polt (20th Century)
Notre Dame
oil or acrylic on canvas
signed lower left
approximately 30 by 30 inches
CONDITION: appears to be in good condition; value assumes no in-painting or flakes to paint.
PROVENANCE: inherited
$300-500*
*represents a fair-market value for auction purposes; retail or asking price may vary.