Even the giant teddy bear at the entrance was not spared, said Ma Jun, who works at a tutoring company in the building.
"Everything is gone and cleaned," she said.
Christmas continues to be a shopping festival across most of China, with huge trees adorning shopping centres in Shanghai and Beijing.
But a growing emphasis on traditional culture by the ruling Communist Party, and the systematic suppression of religion under President Xi Jinping are imperilling Father Christmas's position.
At least four Chinese cities and one county have banned Christmas decorations this year, according to official notices and interviews.
Students, teachers and parents from schools around China told The Associated Press that Christmas celebrations have been curtailed.
"The ongoing local reaction against Christmas is part of the wider sentiment since Xi took power," said Zi Yang, from the S. Rajaratnam School of International Studies in Singapore.
Xi is trying to broaden the appeal of the Communist Party by casting it as a crusader for Chinese tradition in a fast-changing world, he said.
"Therefore, foreign cultural elements such as Christmas are placed on the chopping block."
It appears not to be centrally organised, but rather a spreading resistance to foreign festivals by local authorities seeking to align themselves with the growing tide of cultural nationalism.
The squeeze on Christmas is an example of how efforts to "normalise" thinking bleed into the everyday lives of many Chinese.
That push exploded into view this year through re-education camps for Uighur Muslims and a crackdown on Christian churches that has continued with force in recent weeks.
In Nanyang, about 600 miles west of Shanghai, government officials stopped at the office and shopping complex on December 16 to say that Christmas decorations would have to come down, said Ma, the tutoring company employee.
An official from the city's urban management bureau hung up when asked for comment.
Nine hours by car south, Hengyang, a city in Hunan province, said in a December 19 notice posted on an official government social media account that anyone caught holding Christmas sales or celebrations that blocked the streets would be punished.
Communist Party members, the notice said, should avoid foreign festivals and instead be "models of adherence to Chinese traditional culture".
Hengyang police posted a video on their official social media account of locals discussing the importance of Chinese culture and plans to avoid ostentatious Christmas celebrations.
Langfang city, just south of Beijing, banned Christmas stage performances and merchandising promotions, according to a notice circulated on social media.
Shop windows were to be stripped of Christmas stickers and streets kept free of Christmas banners and lights. Law enforcement patrols were to be stepped up between December 23 and December 25 to prevent illegal signs of celebration.
Police in the Panlong district of Kunming, the capital of Yunnan province in southern China, circulated a notice that hotels, karaoke bars, internet cafes, bars and other crowded places must prohibit Christmas-related decorations and activities.
"It is forbidden to hang Christmas stockings, wear Christmas hats, place Christmas trees, and so on," the notice read.
Students have used social media to complain about restrictions on Christmas celebrations at their schools.
At a top Shanghai university, a student union had its Christmas plans cancelled for the first time, an organiser told the Associated Press.
The students came up with a solution - by replacing Christmas with New Year in their activity proposal and changing the date from December 25, it sailed past school administrators.
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