Marina Ovsyannikova said she had been released a few hours after her arrest.
A Russian journalist, who famously protested against the invasion of Ukraine live on television, was briefly detained over the weekend.
Marina Ovsyannikova said that she had been released a few hours after her initial arrest on Sunday.
"I'm at home. Everything is fine," she wrote on Facebook. "Now I know it's better to leave the house with my passport and a bag."
According to her lawyer Dmitry Zakhvatov, Ovsyannikova was detained on suspicion of "discrediting" the Rusian military. The charges allegedly refer to comments she made in court last week in support of jailed Russian opposition figure Ilya Yashin.
Russian citizens face fines or prison sentences of up to 15 years if they are found to have spread "fake news" about the country's army or entities abroad.
Ovsyannikova generated headlines by bursting on to the TV set of Russia's Channel One in March with a sign reading "Stop the war. Don't trust the propaganda. They lie to you here."
She was later charged with organising an "unauthorised public event" and fined 30,000 roubles (€256).
The journalist has also been seen protesting alone near the Kremlin, holding placards that condemn the war and Russian President Vladimir Putin.
One image posted on Telegram shows the 44-year-old carrying a sign calling Putin a "killer".
Ovsyannikova had left Russia to work for the German newspaper Die Welt, but announced in July that she had returned to the country to resolve a custody battle for her two children.