She was interrogated for 14 hours without access to a lawyer following the incident, and could yet face up to 15 years in prison if she is charged under Russia's draconian new media laws.
"At a crucial moment, Marina Ovsyannikova had the courage to confront Russian viewers with an unembellished view of reality," Ulf Poschardt, editor-in-chief of Welt, said.
"In doing so, she defended the most important journalistic ethics – despite the threat of state repression. I am excited to be working with her."
Ovsyannikova refused an offer of asylum from France following the incident, saying she wanted to stay in Russia.
"Welt stands for what is being so vehemently defended by the courageous people of Ukraine on the ground right now: freedom," she said in a statement.
"I see it as my duty as a journalist to defend that freedom. And I am delighted to be able to do this now for Welt."
Ovsyannikova left her job at Russia's state-run Channel One television following her protest, but by choosing to continue working as a journalist in the country she remains in jeopardy.
The head of news at Channel One has publicly accused her of being a "British spy".
She has continued to describe what Russia claims is a "special operation" in Ukraine as a war and invasion, risking up to 15 years in prison under a new media law passed last month.
She has already been fined 30,000 roubles ($528) over a separate video she posted on social media denouncing the war, and has yet to discover if she will face more serious charges.
In her first report for Welt on Monday, she told how she has faced petty persecution since the protest. Her membership of a swimming pool was revoked, a pet shop refused to supply her with dog food, and she found her car with all four tyres deflated and a flat battery.
She cast doubt on a recent survey claiming 83 per cent of Russians support Putin's war in Ukraine.
"The survey was conducted in a dictatorship. In the middle of a war, when every word against it is seen as treason, for which you will be imprisoned for 15 years," she wrote.
"The Russians are afraid. In Moscow, almost no one picks up when a strange number calls…If suddenly someone shows up or calls and asks 'Do you personally support the military special operation and Vladimir Putin', what will they answer?"
