| Singles | |
|---|---|
| 2017 Brest Challenger | |
| Champion |  Corentin Moutet |
| Runner-up |  Stefanos Tsitsipas |
| Final score | 6–2, 7–6(10–8) |
Norbert Gombos was the defending champion but lost in the first round to Corentin Moutet.
Moutet won the title after defeating Stefanos Tsitsipas 6–2, 7–6(10–8) in the final.
Daniil Medvedev (quarterfinals)
Marius Copil (semifinals)
Norbert Gombos (first round) Jérémy Chardy (quarterfinals)
Malek Jaziri (first round)
Laslo Đere (second round) Andrey Kuznetsov (first round)
Matteo Berrettini (second round)| Semifinals | Final | ||||||||||||
 Yannick Maden | 6 | 62 | 4 | ||||||||||
| WC | Corentin Moutet | 4 | 77 | 6 | |||||||||
| WC | Corentin Moutet | 6 | 710 | ||||||||||
| SE | Stefanos Tsitsipas | 2 | 68 | ||||||||||
| SE | Stefanos Tsitsipas | 77 | 77 | ||||||||||
| 2 | Marius Copil | 62 | 63 | ||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 1 | D Medvedev | 4 | 6 | 6 | |||||||||||||||||||||||
| SE | M Donati | 6 | 1 | 3 | 1 | D Medvedev | 6 | 3 | 77 | ||||||||||||||||||
| B Bonzi | 4 | 7 | 6 | B Bonzi | 4 | 6 | 62 | ||||||||||||||||||||
 A De Greef | 6 | 5 | 3 | 1 | D Medvedev | 61 | 4 | ||||||||||||||||||||
| Y Hanfmann | 6 | 4 | 4 | Y Maden | 77 | 6 | |||||||||||||||||||||
| M Bourgue | 3 | 6 | 6 | M Bourgue | 4 | 2 | |||||||||||||||||||||
| Y Maden | 77 | 6 | Y Maden | 6 | 6 | ||||||||||||||||||||||
| 5 | M Jaziri | 64 | 4 | Y Maden | 6 | 62 | 4 | ||||||||||||||||||||
| 3 | N Gombos | 6 | 4 | 1 | WC | C Moutet | 4 | 77 | 6 | ||||||||||||||||||
| WC | C Moutet | 4 | 6 | 6 | WC | C Moutet | 6 | 66 | 6 | ||||||||||||||||||
| Q |  I Marchenko | 5 | 3 | Q | T Lamasine | 4 | 78 | 3 | |||||||||||||||||||
| Q | T Lamasine | 7 | 6 | WC | C Moutet | 6 | 6 | ||||||||||||||||||||
| Alt | G Sakharov | 6 | 6 | Alt | G Sakharov | 3 | 1 | ||||||||||||||||||||
| WC | D Guez | 2 | 4 | Alt | G Sakharov | 4 | 6 | 6 | |||||||||||||||||||
| WC | G Blancaneaux | 4 | 6 | 1 | 6 | L Đere | 6 | 2 | 2 | ||||||||||||||||||
| 6 | L Đere | 6 | 3 | 6 | |||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 7 | A Kuznetsov | 1 | 3 | ||||||||||||||||||||||||
| SE | S Tsitsipas | 6 | 6 | SE | S Tsitsipas | 6 | 6 | ||||||||||||||||||||
 U Ignatik | 4 | 1 | S Caruso | 3 | 3 | ||||||||||||||||||||||
| S Caruso | 6 | 6 | SE | S Tsitsipas | 77 | 6 | |||||||||||||||||||||
| A Vatutin | 6 | 2 | 1 | 4 | J Chardy | 65 | 4 | ||||||||||||||||||||
| A Giannessi | 4 | 6 | 6 | A Giannessi | 1 | 1 | |||||||||||||||||||||
| LL | A Arnaboldi | 3 | 2 | 4 | J Chardy | 6 | 6 | ||||||||||||||||||||
| 4 | J Chardy | 6 | 6 | SE | S Tsitsipas | 77 | 77 | ||||||||||||||||||||
| 8 | M Berrettini | 6 | 4 | 77 | 2 | M Copil | 62 | 63 | |||||||||||||||||||
| K Kravchuk | 4 | 6 | 63 | 8 | M Berrettini | 3 | 0 | ||||||||||||||||||||
| Q | G Mina | 6 | 63 | 2 | WC | U Humbert | 6 | 6 | |||||||||||||||||||
| WC | U Humbert | 3 | 77 | 6 | WC | U Humbert | 4 | 4 | |||||||||||||||||||
 A Šetkić | 6 | 66 | 4 | 2 | M Copil | 6 | 6 | ||||||||||||||||||||
| L Vanni | 2 | 78 | 6 | L Vanni | 62 | 1 | |||||||||||||||||||||
| Q | Yannik Reuter | 3 | 4 | 2 | M Copil | 77 | 6 | ||||||||||||||||||||
| 2 | M Copil | 6 | 6 | ||||||||||||||||||||||||
Mikhail Kukushkin was the defending champion but chose to compete in the 2014 Aegon Championships instead.
Kenny de Schepper was the defending champion, but lost in the quarterfinals.
The previous year's runner-up Norbert Gombos won the title, defeating Benoît Paire in the final, 6–1, 7–6(7–4).
Nick Kyrgios was the defending champion, but lost in the semifinals to Jo-Wilfried Tsonga.
This was the first edition of the tournament.
Feliciano López was the champion in 2014, when the men's event was last held, but withdrew before the tournament began.
Pierre-Hugues Herbert was the defending champion but lost in the second round to Illya Marchenko.
Norbert Gombos was the defending champion but lost in the first round to Jerzy Janowicz.
Alexander Zverev was the defending champion, but chose not to participate this year.
Jo-Wilfried Tsonga was the defending champion, but withdrew before the tournament began.
Norbert Gombos was the defending champion but lost in the first round to Luca Vanni.
This was the first edition of the tournament.
Alexander Zverev was the two-time defending champion but chose not to defend his title.
Aljaž Bedene was the defending champion but lost in the quarterfinals to Mikael Ymer.
Elias Ymer was the defending champion but chose not to defend his title.
Hubert Hurkacz was the defending champion but chose not to defend his title.
Stefanos Tsitsipas was the defending champion and successfully defended his title, defeating Félix Auger-Aliassime in the final, 6–3, 6–4.
Nikoloz Basilashvili defeated Roberto Bautista Agut in the final, 7–6(7–5), 6–2 to win the men's singles tennis title at the 2021 Qatar Open.
Nikoloz Basilashvili defeated Jan-Lennard Struff in the final, 6–4, 7–6(7–5) to win the men's singles tennis title at the 2021 Bavarian International Tennis Championships. This was Basilashvili's second title on the 2021 ATP Tour.
This was the first edition of the tournament, primarily created due to the one-week delay of the 2021 French Open.
Taylor Fritz was the defending champion from when the event was last held in 2019, but withdrew before the tournament with a knee injury.