| Date: | 6 April – 12 April |
| Edition: | 12th |
| Draw: | 32S / 16D |
| Surface: | Hard |
| Prize Money: | €35,000+H |
| Location: | Saint-Brieuc, France |
| Champs: |  Nicolas Mahut |
| Champd: | Grégoire Burquier / Alexandre Sidorenko |
| Main Name: | Saint-Brieuc Challenger |
The 2015 Open Harmonie mutuelle was a professional tennis tournament played on hard courts. It was the twelfth edition of the tournament which was part of the 2015 ATP Challenger Tour. It took place in Saint-Brieuc, France between 6 April and 12 April 2015.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| France | 114 | 1 | ||
| 116 | 2 | |||
| France | 124 | 3 | ||
| 132 | 4 | |||
 Japan | Yūichi Sugita | 147 | 5 | |
 Czech Republic | Jan Hernych | 178 | 6 | |
| France | 191 | 7 | ||
 United Kingdom | Edward Corrie | 218 | 8 |
The following players received wildcards into the singles main draw:
Grégoire Barrère Grégoire Burquier Quentin Halys Laurent RochetteThe following players received entry from the qualifying draw:
| Country | Player | Country | Player | Rank | Seed | |
|---|---|---|---|---|---|---|
| Wesley Koolhof | Matwé Middelkoop | 324 | 1 | |||
| Ruben Gonzales | United Kingdom | Darren Walsh | 345 | 2 | ||
| Andreas Beck | United Kingdom | Ken Skupski | 369 | 3 | ||
 Poland | Andriej Kapaś | Japan | Yasutaka Uchiyama | 390 | 4 |
The following pairs received wildcards into the doubles main draw:
Grégoire Barrère / Marc Gicquel Rémi Boutillier / Quentin Halys Grégoire Burquier / Alexandre SidorenkoSee main article: 2015 Open Harmonie mutuelle – Singles.
Nicolas Mahut def. Yūichi Sugita, 3–6, 7–6(7–3), 6–4See main article: 2015 Open Harmonie mutuelle – Doubles.
Grégoire Burquier / Alexandre Sidorenko def. Andriej Kapaś / Yasutaka Uchiyama, 6–3, 6–4