Outside the European Parliament in Brussels, an empty pole stands in between the flags of the remaining 26 EU member states, the Metro newspaper said in the report on Saturday.
The office of UK Representation to the EU has been renamed the British diplomatic mission, in a nod to the next phase of negotiations.
In Strasbourg, staff wasted no time in taking down the Union Jack, which disappeared hours before the Brexit deadline on January 31.
The historic split happened 11 p.m. on January 31 and was marked with both celebrations and protests across the UK.
The country is now at a "turning point" as it enters an 11-month transition period in which it must hammer out a new relationship with former partners.
Britain is now formally no longer a member of the EU but normal life will remain the same for some time.
The UK will remain in the single market and the customs union until the end of the year as part of the divorce agreement, the Metro newspaper report added.
Prime Minister Boris Johnson has a year to hammer out a new relationship with Brussels and is seeking a Canada-style free trade deal.
He is set for a collision course with EU member states who would prefer a deal that is more closely aligned with the bloc's rules.
The UK had joined what was then European Economic Community on January 1, 1973, at the third attempt.
Two years later the country voted by an overwhelming majority to remain in the bloc in the first nationwide referendum.
( With inputs from IANS )