I think that wartsilasulzer means that Bretagne is a multi-purpose frigate but that in the NATO ranking, because of her tonnage she is classified destroyer (Pennant number D655).
The term destroyer is not used in the French navy for its ships.

What is a multi purpose Frigate/Destroyer ?

Bravo! Good copy/paste.

FS BRETAGNE D655
FREMM CLASS multipurpose frigate / destroyer
Builders: France and Italy
Operators: French Navy / Italian Navy / Royal Moroccan Navy / Egyptian Navy
Preceded by: Georges Leygues class (France) / Cassard class (France) / Lupo class (Italy) / Maestrale class (Italy)
Cost:
€670m/unit FY 2014 France
€598m/unit FY 2016)(Italy
€470m/unit Morocco
Built: 2007-
In commission: 2012-
Planned: 20 (Italy 10, France 8, Morocco 1, Egypt 1)
Cancelled: 9 out of originally 17 for the French navy
Active: 13 (Italy 7, France 4, Morocco 1, Egypt 1)
General characteristics
Type: Frigate / Destroyer
Displacement:
France: 6,000 tonnes
Italy: 6,700 tonnes (light displacement 5,500 tonnes)
Length:
France: 142 m LOA
Italy: 144.6 m LOA
Italy: 132.5 m LPP
Beam:
France: 20 m
Italy: 19.7 m
Draught:
France: 5 m
Italy: 8.7 m
Draft: Italy: 5.1 m
Propulsion:
France: CODLOG
Italy: CODLAG
1 × 32 mws gas turbine General Electric/Avio LM2500+G4
2 × 2.5 mws electric motors Jeumont Electric
4 × diesel generators
France: MTU Series 4000 (2,2 mws everyone)
Italy: Isotta Fraschini VL 1716 (T2ME series by 2,15 mws everyone, on first two frigate; HPCR series by 2,8 mws everyone, since the third frigate)
2 × shafts, driving controllable pitch propellers
1 × 1 mw bow thruster
Speed:
France: max +27 knots (50 km/h; 31 mph); max cruise speed 15.6 knots (28.9 km/h; 18.0 mph)
Italy: max +30 knots (56 km/h; 35 mph); max cruise speed +17 knots (31 km/h; 20 mph)
Range:
France: 6,000 nmi (11,000 km; 6,900 mi) at 15 knots (28 km/h; 17 mph)
Italy: 6,800 nmi (12,600 km; 7,800 mi) at 15 knots (28 km/h; 17 mph)
Complement:
France: 145
Italy: 199 GP version / 201 ASW version
Crew: Italy: 131 GP version / 133 ASW version; add 14 crew for one helo on board or add 23 crew for two helos on board
Sensors and processing systems:
France: Héraklès multi-purpose passive electronically scanned array radar
Italy: Leonardo Kronos Grand Naval (MFRA) Active electronically scanned array radar
Armament:
Anti-air missiles:
France: 16-cell MBDA SYLVER A43 VLS for 16 MBDA Aster 15 missiles
Italy: 16-cell MBDA SYLVER A50 VLS for 16 MBDA Aster 15 and 30 missiles
Guns:
France: 1 × Leonardo OTO Melara 76 mms SR gun
Italy: 2 × Leonardo OTO Melara 76/62 mms Davide/Strales CIWS guns (ASuW variant)
1 × Leonardo Otobreda 127/64 Vulcano and 1 × Leonardo OTO Melara 76/62 mms Davide/Strales CIWS gun (GP variant)
Small guns:
France: 3 × Nexter 20mms Narwhal remote weapon systems
Italy: 2 × Leonardo Oto Melara/Oerlikon KBA 25/80 mms remote weapon systems
Anti-ship missiles:
France: 8 × MBDA MM-40 Exocet block 3 anti-ship missiles
Italy: 8 × MBDA TeseoOtomat Mk-2/A anti-ship and land attack missiles
Land-attack cruise missiles:
France: 16-cell MBDA SYLVER A70 VLS for 16 MBDA SCALP Naval land-attack cruise missiles
Anti-submarine warfare:
France: 2 x double Leonardo (WASS) B-515 launcher for MU 90 torpedoes
Italy: 2 x triple Leonardo (WASS) B-515/3 launcher for MU 90 torpedoes and (only ASW variant) 4 x MBDA Milas missiles
Italy: 2 x SITEP MASS CS-424 acoustic guns (update since 2017)
Aircraft carried:
France:1 × NH90
Italy: 2 × SH90 or 1 × SH90 and 1 × AW101 (armed with MU 90 torpedoes or MBDA Marte Mk2/S missiles)
Aviation facilities:
France: single hangar
Italy: double hangar