Coquelin and Djourou sent to Germany on loan
French midfielder Coquelin, who has featured 43 times since joining the Londoners as a 17-year-old in 2008, will aim to gain more experience and build up his playing time, the club said on their website on Friday.
Freiburg finished fifth in the league last season.
Switzerland defender Djourou, who spent the second half of last term on loan at Hannover 96, heads back to the Bundesliga with Hamburg who were seventh when the campaign ended in May.
"Everyone at Arsenal would like to wish Johan the best of luck," the club added.