The lower house of parliament has tightened access to civilian service, mirroring earlier decisions by the National Assembly.
Civilian service is often chosen by those who want to avoid compulsory military service.
The upper chamber voted in favour of a reform that slashes annual admissions from 6,600 to 4,000.
Soldiers who’ve already completed training days can no longer switch, and anyone converting must serve at least 150 days - one and a half times longer than military service.
Civilian service will also be spread across years, and assignments in medicine are now banned.
Supporters say the move restores civilian service to its original purpose.
The left calls it an unjustified attack that undermines healthcare and environmental work.
The Young Greens say they will launch a referendum against the plan, saying there are already enough soldiers, with 151,000 ready right now.
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