When Susie got the phone call in the previous episode to make the breakthrough booking that is the focus of this episode, the plan was clearly for February. Yet in this episode Abe and Rose have been in Paris for so long that the springtime blossoms are coming out in the parks. It is not specified what month the action occurs in, but somehow Abe suddenly has to return to New York because classes at Columbia are about to start - which would normally be either January or September. That is, if he had managed to arrange a spontaneous springtime sabbatical, then they could have stayed in Paris all through the summer, which they did not, but nor did he hurry home for the winter semester. Basically, several months were inserted on the Paris side that did not occur on the New York side.
When Rose and her group visit the Rodin Museum, they stop in front of the "Burghers of Calais" monument in the forecourt of the Museum. In around 1960, this sculpture was displayed elsewhere (moved to forecourt in the 1980s).
Ginger reads an article in The Village Voice to Midge quoting Susie that "Mrs. Maisel...will be bigger than Totie Fields." As the timeline of the plot now seems to take place in the first half of 1959, Totie Fields would certainly not have been "big" or well-known then as her career did not really start until the early 1960s.