German underpaid postcard... or a New Year Bank Holiday too long?

Between January 18th and Saturday 23rd, I received this Postcrossing postcard from Germany with a mark indicating an insufficient postage.

Schloss Ludwiglust stamp at 80 eurocents double cancelled in Bremen.

Believing Postcrossing tools, the card was asked by Lara on Wedenesday December 23rd 2015. On a group of 69 cards I sent to German Postcrossers and 68 received since 2007, the trip from asking to registering is seven days.

One month's surprising.

Deutsche Post's postage calculator and its parent website provided the cause of the problem: since the beginning of the new year, the international rate rose from 80 cents to 90 cents. The stamp - a picture of Ludwigslust Castle in Mecklemburg - does not cover it completely, hence the taxation mark "T 10/90".

Now the cancellation from Briefzentrum 28 is the common pictorial cancel of Bremen mail center 28 and 29. On the left side of the mark is the map of both postal zones: 28 being the city of Bremen and 29 the neighbouring Landkreise of Lower Saxony. The main part of the illustration is the statue of the Town Musicians of Bremen, by the Grimm brothers' tales. Philastempel.de proposed a clearer view here.

Clearer because mine is double cancelled but I think not on the same day. I can decipher the same "-1 16" that would mean the card arrived at the mail center in January, new rate then. But one of them was surely stricken on the 5th...

The double cancel and the fact that the French post didn't ask me anything would mean that perhaps the postal operators decided that the long New Year week end, from Thursday afternoon to Monday morning may have lost some consumers.

Thank you Lara for the very nice and thankful card, and a late mailboxing that ended with the postage due mark. Thank you to La Poste or Deutsche Post to avoid me paying it or to avoid defacing the card with any sticker or huge announcement mark you're using these days.

I just wish that La Poste will put back illustrated cancellation on French mail.