Maison Batard was never meant to be this big.

In 2018, when livewire restaurateur Chris Lucas took over a slim, split-level Victorian terrace at the top end of Bourke Street, he envisaged a little French bistro and wine bar.

Fast forward six years and it’s snowballed into the flagship of Lucas’ eponymous restaurant group, which includes the two-hatted Society, Grill Americano and Chin Chin, as well as the recently opened Tombo Den and Carlotta in Canberra.

As Lucas acquired and amalgamated two additional historical buildings – to the right and behind the original – Maison Batard burgeoned into a once-in-a-career restaurant.

It will finally open on November 26. “This, as it’s turned out, is a legacy project,” Lucas says. “There’s not another one of these in me ... so I’ve given it everything I’ve got.”

COVID wrought havoc on the restaurant industry, but it did give Lucas one gift: time. To refine, to reorient, “to think about what’s possible, rather than what’s probable”. Then, to lead his team on a hedonistic research romp through Paris: 27 venues in five days.

Now spanning four storeys – with two restaurant levels, a rooftop terrace that feels like that of a five-star hotel and a slinky subterranean supper club – Maison Batard is Lucas’ most involved undertaking yet. But it also feels like his most intimate.

As a lifelong Francophile, Lucas’ extensive travels through France are built into the DNA of Maison Batard, from the overall concept to the wine pulled from his personal collection.

But it was checking into the achingly elegant, art-adorned Hotel Particulier, in the Parisian neighbourhood of Montmartre, that left an indelible mark on Lucas. The grand old mansion and its jungle-like grounds inspired the evolution of Maison Batard into not just a restaurant, but a “dining house” with many strands.

Just off Bourke Street, in the ground-floor restaurant, there’s an air of French brasserie style, rather than an ambush. Smoky-mirrored walls flank the wide room and its Tetris of plump velvet booths, but it’s an icy mountain of molluscs that will draw your attention.

The custom-built oyster bar will offer 10 varieties shucked to order, from the “entry-level” Pacific to the “exquisite” belon, sourced directly from contracted growers. They’re priced by the shell, alongside Skull Island prawns and southern rock lobster, making for customisable fruits de mer (seafood) platters.

To drink while you think, the roving aperitif trolley will pour Drouet pineau des charentes – a marriage of wine and cognac seldom seen in Australia – and the brilliantly named Dirty Batard martini, as briny as it sounds but with a herby hit of French chartreuse.

Scanning the sizeable menu, French favourites abound. There’s piquant, delicately diced beef tartare; dinner-appropriate omelettes, either folded with hunks of lobster or slivers of fried potato; and luscious Valrhona dark-chocolate mousse, served tableside studded with chocolate shards and dolloped with Chantilly cream.

But tradition is less binding here than at many of the city’s time-honoured French bistros. “There’s always a Melbourne overlay with everything I do,” Lucas says. “Chin Chin’s not a David Thompson Thai restaurant where the heat blows your head off.”

At Maison Batard, “I’ve gone more provincial [French] ... I think it suits today’s style,” Lucas says. As in Mediterranean cooking, olive oil reigns, butter takes a back seat and cream is (mostly) relegated to dessert.

“It’s all about lightening and freshening it up,” says British-born executive chef Adam Sanderson (Noma, The Fat Duck, Ten Minutes by Tractor). “And it really comes down to sauces and dressings – that finishing touch.” Some dishes, such as the yuzu-spiked tuna tartare, throw Asian influences into the mix.

And as for the signatures? A Josper-fired chateaubriand stars prime Riverina eye fillet. Whole Bannockburn chickens, hypnotising diners on a full-view rotisserie, are served simply in their juices with green olives. And, after diving into the science of fries to decipher what’s superior and scalable for a restaurant this size, the result is skin-on, hand-cut and as thin a shoestring as possible without needing to employ a full-time staffer on frites duty.

Up a staircase that spirals through all four levels – what Lucas calls a “big Instagram moment” – another restaurant space awaits on the first floor, with the same menu as below but a decidedly different look. Hung from the vaulted ceiling is a Parisian chandelier that Lucas found “busted-up but beautiful” while vintage shopping in Milan. Its restoration cost three times the purchase price.

The real showstopper, though, is the rooftop. French doors fling open onto the main terrace, bathed in light and with a 50-year-old maple tree, grown in the Yarra Valley, craned into its centre.

A distinct, all-day terrace menu dials up the joie de vivre with crowd-pleasers such as cheeseburgers and baked potatoes, done deftly. The former, Lucas insists, has been engineered so it does not drip. The latter has a crown of caviar – “no bumps”.

Servicing this level is a sunken bar and a tableful of beautiful ice buckets with (strictly French) rosé and champagne, the list running from stalwarts such as Krug and Dom Perignon to prestige cuvee Rare Millesime, with vintages going back to 1998.

Thanks to the Coravin system, Maison Batard’s by-the-glass wine list surpasses 200, making it what Lucas says is one of the biggest in the country. The bottle list goes deep, too, balancing key French and Australian players with a diversity of vintages. “It’s not just about having the top burgundies,” says Loic Avril, Lucas Restaurants’s head of wine.

Another focus is cognac, and championing smaller producers in the French region, which will be poured on a second, smaller cigar terrace set against the Bourke Street treetops.

Having to dig down to restore the heritage building’s foundations prompted Lucas to double down, too, adding a basement. From New Year’s Eve, it will be a late-night lure for dinner and a show, with a grand piano on its small stage and scallop-edged booths for lounging.

It’s taken the better part of a decade, but Lucas has turned the tide for a spot steeped in Melbourne hospitality history. From 1927 to the mid-’80s, it was home to the original Italian Society – a power-dining destination for politicians, celebrities and business people – which he says “ushered in the first era of European dining in Melbourne”.

He preserved the name with his own high-flying Society restaurant. And now the site itself, with Maison Batard.

It’s a multimillion-dollar investment in resurrecting the glory days of the heritage-listed Bourke Hill Precinct, which encompasses Parliament House, the Hotel Windsor, the surrounding theatres, and institutions such as Pellegrini’s and Florentino.

“I know everyone talks about Flinders Lane, but this is a more elegant, proper boulevard,” Lucas says. “This is Melbourne’s pre-eminent area.”

But swinging for the fences with Maison Batard is as much about the mark he hopes to make on Melbourne as the mark he hopes Melbourne can make on the world.

“There’s no use building more and more Chin Chins,” Lucas says. “They’re good, they’re great. But they serve a different purpose.”

“In the latter part of my career, maybe the end of my career ... I want to leave a lasting legacy.

“And, to me, a lasting legacy is restaurants that are putting us on the map internationally.”

Open daily noon-late, from November 26.

23 Bourke Street, Melbourne, maisonbatard.com.au