"School of Martin van Meytens" is Workshop of Jean-Baptiste Santerre

Quentin, from Germany, sells on 20 October 2018 a "School of Martin van Meytens" Portrait of a Smoker, a relatively large (100 by 80 cm) work estimated at 1,600 Euro.

They have used it as the cover of their catalogue, and it is an attractive work. It doesn't seem to be from the School of Meytens (1695-1770) though, his style is related but different, with more clearly delineated features, more stark blacks and less smokey sfumato. He also nearly always painted stately portraits, not this kind of genre portrait in a much more informal atmosphere.

Luckily the RKD has a better version of the painting for sale in their database. It was sold at Sotheby's Monaco in 1987, and is by Jean-Baptiste Santerre (1651-1717).

He was a typical (though very good) painter of the early French Rococo, known for portraits (top image is his self portrait) and slightly risqué nudes.

Another(?) version of the painting is located in a private collection in castle Bouzillé in the French Anjou region, according to "pipegazette.com"

The painting for sale lacks the finesse and shining finish one can see in the Sotheby's version, so presumably this isn't an original by Santerre but a copy. It is good though, so this kind of thing then usually gets labeled "workshop copy" no matter if the artist actually had a workshop which ever created copies or not...

The version for sale should fetch 6,000 to 8,000 Euro. 

UPDATE: Sold, with my attribution, at Dorotheum in 2019 for 13635 Euro. Previous sale not listed in provenance though. 

"Flemish genre painting" is by a Follower of the Master of the Female Half-Lengths

Quentin, from Berlin, Germany, sells on 22 April 2017 a "Flemish genre painting, ca. 1600" of a merry company, estimated at 3,500 to 5,000 Euro.

The work is a variation on a painting sold at Sotheby's London in 2013, which was then attributed to the Master of the Female Half Lengths. It sold for £86,500.

Another, more elaborate version with the story of the Prodigal Son, is kept in the Musée Carnavalet and has been attributed in the past to the same master, or Jan van Hemessen, or Quentin Massys, or the Monogrammist of Brunswick. This version lacks the jester with his marotte though. But it does have what seems to be Paris in the background (the Notre Dame!), which explains what it does in the Musée Carnavalet, which is a historical museum first and foremost.

While the original artist is thus clearly unidentified, the work for sale is a copy of lesser quality, but with some interesting variations which may help people define the original artist (if these variations are based on some original version of course). The exact allegorical meaning isn't really clear to me, but women, alcohol and music all seem to be foolish things to get involved with. Perhaps it is simply another Parable of the Prodigal Son. The estimate may be somewhat high for a clearly less skilled artist, but it is an interesting old work anyway and should be worth a few thousand Euros.

Copy of Kupecky

At Quentin from Berlin, they sell a "Dutch, 17th / 18h century" portrait of the painter and his family, estimated at 3,000 Euro.

It is a good copy (but probably not good enough to be an original) of a well-known painting by Jan Kupecky (1667-1740, also known as Johann Kupetzki) from the Budapest Museum of Fine Arts. I have found no evidence of other old copies of this painting, which is quite remarkable and unusual (not many current artists would paint a family portrait like this probably, but I guess it is meant symbolic). Whether it is worth more than the estimate is not clear though.