"This government taking office marked a turning point" in combating illegal immigration, Castaner told the National Assembly, taunting the right-wing opposition that Emmanuel Macron's administration had provided extra resources, while "some people prefer talk".
The number of deportations went up 14 percent to 14,859 in 2017 and has risen 20 percent so far this year, he explained.
Castaner recently took over from Gérard Collomb, who has become mayor of the central city of Lyon.
The immigration law, which Collomb piloted through parliament despite vociferous opposition, aims to reduce the time taken to deal with asylum requests to six months, compared to 11 months at the beginning of this year, and was presented as a way of treating justified applicants more fairly while cracking down on false claims.
There were 100,000 asylum applications in 2017, a rise of 17 percent on the previous year.
Two hundred extra places in retention centres have been created since October 2017, Castaner said and 48 million euros are to be invested in them.
The total budget for handling immigration is to rise 13 percent to 1.58 billion euros.
An Italian people-smuggler was jailed for three years in the south of France on Tuesday.
He was stopped on a French motorway driving a van with 20 people of Pakistani origin, including four children, locked in the back.
An Indian national who was arrested with him has not been charged but has been ordered to leave the country as have the Pakistanis.
The Italian will be banned from entering France for 10 years after he has served his sentence.
Seven activists to stand trial
The trial of seven rights activists charged with helping "the illegal entry of foreigners into national territory" opens on Thursday.
The seven - four French nationals, one Italian, one Swiss and one Belgian-Swiss - could face up to 10 years in prison and fines of up to 750,000 euros.
They are accused of helping about 20 migrants enter France as part of a demonstration that crossed the border from Italy in response to a far-right group's blocking of a nearby mountain pass a day before.
They argue that the migrants joined the march of their own accord and that they all had a right to demonstrate.
A number of activists have faced trial for helping migrants and claimed the right to exercise solidarity as their defence.
One of Thursday's defendants was acquitted last month in a case brought because he helped a pregnant Nigerian woman in weather the court described as "hazardous".