Senegal's president has criticised a French plan to carry out voluntary DNA testing of would-be immigrants who want to join their families in France.
The DNA testing is part of a tough new immigration bill
"It is a serious mistake," Abdoulaye Wade is quoted by the French news agency as saying.
Trying to scientifically prove one's kinship was "not respectful of human freedom", he said.
The upper house of the French parliament is due to consider the DNA measure later on Tuesday.
The idea, part of a tough new immigration bill, was approved by the lower house last month.
DNA testing is intended to speed up the visa application process for would-be immigrants.
But critics believe such tests would exclude many people unable to pay for the test.
The new bill has been criticised by some members of President Nicolas Sarkozy's centre-right government.
The legislation would require immigrant family members older than 16 to take a test in their country of origin, demonstrating a good knowledge of French language and values.
Applicants would also have to prove that their family in France could support them and earn at least the minimum wage.
Mr Sarkozy has set up deportation quotas, promising to send home 25,000 illegal immigrants this year alone.
He says France, like a number of other Western countries, needs to choose the immigrants it needs.
Thousands of illegal migrants, many risking their lives on dangerous journeys, try to reach Europe from Africa each year.