The action comes after French police closed down several Roma camps around the country, with many seeking refuge in a gymnasium outside Paris.
The plan is part of president Nicolas Sarkozy's controversial crackdown on Roma communities, which he described as sources of trafficking, exploitation of children and prostitution.
But human rights groups and politicians have criticised the move, accusing the French government of picking on a minority population.
Teodor Baconschi, Romania's foreign minister, said he was worried about the risk of "xenophobic reactions".
"It does stigmatise an entire group ... For most people it's upsetting, humiliating, traumatic, to be uprooted and be thrown out of the country"
Author, Little Money Street
"I am worried about the risks of populism and xenophobic reactions in a context of economic crisis," he told the Romanian service of Radio France International (RFI Romania).
Human rights groups and media in Bulgaria also criticised France's handling of the Roma issue.
Krasimir Kanev, head of rights watchdog the Helsinki Committee in Bulgaria, said he was "worried by the measure aimed at an ethnic group".
Fernanda Eberstadt, the author of Little Money Street, a book based on the Roma community in France, told Al Jazeera the crackdown was a "classic scapegoating of a vulnerable minority".
"It does stigmatise an entire group ... For most people it's upsetting, humiliating, traumatic, to be uprooted and be thrown out of the country."
She added the move "has echoes" of the round-ups and removals of Roma that took place in Nazi-occupied France during World War II.
Around 10,000 Roma from Romania and Bulgaria returned to their countries using the "voluntary return" procedure last year, but Thursday's move is the first since Sarkozy launched a crackdown on the community.
Baconschi said he "hopes" that all legal procedures have been duly applied for these "expulsions".
Fears of discrimination
The French foreign ministry has insisted that the measures being taken against the Roma were in line with European rules.
"The measures taken by the French authorities with regard to dismantling illegal camps fully conform with European rules and do not in any way affect the freedom of movement for EU citizens, as defined by treaties," Bernard Valero, foreign ministry spokesman, told the AFP news agency.
Valero said a European directive "expressly allows for restrictions on the right to move freely for reasons of public order, public security and public health".
The EU's executive arm, the European Commission, said it was following the situation "very attentively", adding that France must abide by the bloc's freedom of movement rules when it expels Roma living illegally in the country.
There are about 15,000 Roma of Eastern European origin in France.
The Roma community in Romania numbers 530,000 according to the national census or 2.5 million according to non-governmental organisations, who say that some do not declare themselves as Roma, fearing discrimination.