"Signed portrait of an ancestor" is probably self portrait by Léon Herbo

Mosan, from Belgium, sells on 13 November 2019 a "Signed portrait of an ancestor" estimated at 200 to 300 Euro.

They don't give any indication of period or an attempt to read the signature, but the painting is signed by Léon Herbo (1850-1907), a Belgian painter (sometimes erroneously said to be French though) most famous for portraits, and for romantic or exotic females.

"The wedding feast", offered at Sotheby's in 2016 for $60,000

"Salomé", sold at Christie's in 2004 for £17,000

His best (and most expensive) works were made before 1890, his later work tends to be less well executed.

 

Another self-portrait in similar clothing, for sale at Diederiks for 7,500 Euro 

This work is dated 1883 (the same year he won the Gold Medal at the Salon of Brussels), and is most likely a self-portrait. His normal portraits are more straightforward, only in his self portraits do we see a more whimsical side, with the artist dressing up as a character. Other self-portraits all seem to be somewhat later, which explains differences in e.g. the moustache (and the painting style), but basically we are looking at the same person.

The painting sadly has some damage, but even so it should be worth 2,000 or more, considering that his more attractive paintings fetch between 5,000 and 15,000 Euro.