French prosecutor Eric Maillaud said he was released from police custody after investigators found "no direct link" between him and the events in 2012.
Mr Maillaud said:
"The searches and interviews of the last three days have not enabled us to establish a direct link between the events of 5 September 2012 and this man, a war weapons enthusiast, who looked very like the e-fit released and who was near to the place where the incident took place when it happened.
"However, the man will be taken into custody, overseen by the public prosecutor's office in Annecy, in connection with illicit trading in wartime weapons and ammunition found during searches by investigators, this illicit activity being carried out as part of an organised gang."
A second man arrested earlier this week in connection with alleged arms trading remains in custody.