Italy’s UniCredit appears to have caught German authorities off guard with a potential multibillion-euro merger of Frankfurt-based Commerzbank, a move that has triggered a fiery response from Berlin.

Market observers told CNBC that the swoop may have provoked a sense of national embarrassment among Germany’s government, which firmly opposes the move, while it’s been argued that the outcome of the takeover attempt could even put the meaning of the European project at stake.

Milan-based UniCredit announced on Monday that it had increased its stake in Commerzbank to around 21% and submitted a request to boost that holding to up to 29.9%. It follows UniCredit’s move to take a 9% stake in Commerzbank earlier this month.

“If UniCredit can take Commerzbank and take it to their level of efficiency, there’s a tremendous upside in terms of increased profitability,” Octavio Marenzi, CEO of consulting firm Opimas, told CNBC’s “Squawk Box Europe” on Tuesday.

“But [German Chancellor] Olaf Scholz is not an investor. He’s a politician and he’s very concerned about the jobs side of things. And if you look at what UniCredit has done in terms of slimming down things in its Italian operations or particularly in its German operations, it’s been quite impressive,” Marenzi said.

Scholz on Monday criticized UniCredit’s decision to up the ante on Commerzbank, describing the move as an “unfriendly” and “hostile” attack, Reuters reported.

Commerzbank’s Deputy Chair Uwe Tschaege, meanwhile, reportedly voiced opposition to a potential takeover by UniCredit on Tuesday. Speaking outside of the lender’s headquarters in central Frankfurt, Tschaege said the message was simple and clear: “We don’t want this.”

“I feel like vomiting when I hear his promises of cost savings,” Tschaege reportedly added, referring to UniCredit ‘s CEO Andrea Orcel.

Separately, Stefan Wittman, a Commerzbank supervisory board member, told CNBC on Tuesday that as many as two-thirds of the jobs at the bank could disappear if UniCredit successfully carries out a hostile takeover.

The bank has yet to respond to a request for comment on Wittmann’s statement.

Hostile takeover bids are not common in the European banking sector, although Spanish bank BBVA shocked markets in May when it launched an all-share takeover offer for domestic rival Banco Sabadell. The latter Spanish lender rejected the bid.

Opimas’ Marenzi said the German government and trade unions “are basically looking at this and saying this means we could lose a bunch of jobs in the process — and it could be quite substantial job losses.”

“The other thing is there might be a bit of a national embarrassment that the Italians are coming in and showing them how to run their banks,” he added.

A spokesperson for Germany’s government was not immediately available when contacted by CNBC on Tuesday.

Germany’s Scholz has previously pushed for the completion of a European banking union. Designed in the wake of the 2008 global financial crisis, the European Union’s executive arm announced plans to create a banking union to improve the regulation and supervision of lenders across the region.

Former European Central Bank chief Mario Draghi said in a report published earlier this month that the European Union needs hundreds of billions of euros in additional investment to meet its key competitiveness targets.

Draghi, who has previously served as Italian prime minister, also cited the “incomplete” banking union in the report as one factor that continues to hinder competitiveness for the region’s banks.

— CNBC’s April Roach contributed to this report.