The Sarkozy-Bruni family made a splash in Washington DC this week with a trip to Ben's Chili Bowl, adding another chapter to the shabby hotdog joint's storied history. As Les Echoes noted, the restaurant "fréquenté en son temps par Martin Luther King".

Sadly, the only problem with Ben's Chili Bowl is that while the atmosphere is great, the food is mediocre, even by fast food standards. The signature "chili" is oily and very salty, and is itself mild but served at a ferociously hot temperature. Le Monde's Washington correspondent summed it up pretty well: "une institution devenue assez touristique où l'on mange des hot-dogs".

Still, the other option for Sarkozy was lunch at the White House with noted raconteur Tim Geithner and his gang of econo-wonks. Even Ben's nuclear chili sounds good in comparison.

Ben's, though, has a hell of a backstory, as part of the neglected African-American heritage of Washington DC. It was opened in 1958 by an immigrant from Trinidad, Ben Ali, a dental student at nearby Howard University, and his wife Virginia. But the reason it's a landmark (apart from sheer longevity) is its role in DC's U Street corridor, once known as the "black Broadway". The restaurant's website recounts:

Top performers could be found playing sets in clubs along the corridor, as well as eating and just "hanging out" at Ben's. It was not uncommon to see such luminaries as Duke Ellington, Miles Davis, Bessie Smith, Ella Fitzgerald, Cab Calloway, Nat King Cole, Redd Foxx, Dick Gregory, Martin Luther King Jr or Bill Cosby at "The Bowl."

Bill Cosby was a regular visitor, and for years a notice hung behind the counter reading: "List of who eats free at Ben's: Bill Cosby. No one else". In 2008 the sign was amended to add the Obama family to the list – although when Obama himself did visit, before his presidential inauguration in 2009, he paid in full.

Washington was convulsed by race riots in 1968, along with many other parts of the US, in the wake of King's assassination. Ben's was one of the few businesses to stay open during the riots that devastated sections of the capital. The restaurant's website says: "Stokely Carmichael of the Student Non-Violent Coordinating Committee, which was located across the street, obtained special police permission to allow Ben's to stay open after curfew to provide food and shelter for activists, firefighters and public servants desperately trying to restore order."

Since then the restaurant has appeared as local colour in movies – the most recent being State of Play – and has turned into a stop on the Washington tourism trail as well as being a late-night fast food joint. In 2008 the Ali family opened another restuarant and bar, called Next Door, which is rather more up-market, in keeping with the gentrification of the U Street corridor.

The other notable event of the Sarkozy déjeuner was Carla Bruni's delight at the half-smoke sausage in her hotdog – the half-smoke being Washington DC's sole indigenous contribution to world cuisine.

What's a half-smoke? The funny thing is no one can agree on anything other than the fact that it's a Washingtonian delicacy. The Washington City Paper wrote an exhaustive article on the subject:

Depending on whom you ask, the half-smoke is simply a smoked sausage. Or it's a sausage that's been smoked only halfway — whatever that could possibly mean. Or maybe it's a half-smoke because some cooks prefer to split it in half when it goes on the grill. Or its "half" comes from the fact that it's often made from equal portions of beef and pork. But then how do you explain all those half-smokes downtown that are advertised as all-beef?

So, no-one knows – but whatever they are, you can buy half-smokes at every hotdog stand in the District. They taste slightly spicier than normal franks.

So if you want to avoid the crowds, and eat some decent fast food, where to go in DC? For locals the chain of choice is often the Five Guys burger bar, with multiple outlets around Washington, where a custom-made burger, fries and Coke can be had for $10. The Obamas go for Five Guys burgers on a regular basis – both Barack and Michelle. The fries are excellent. And the hotdogs are pretty good too. Or there's the huge Lauriol Plaza, a longstanding Mexican restaurant on 18th Street in Adams Morgan – a favourite of Bill Clinton's.

Update: My colleague Saptarshi Ray points out in comments below that I didn't mention a personal favourite fast food place: the Well Dressed Burrito. The WDB is very good indeed – try the "daily special" burrito for $6.25. But because it's hard to find, hidden away down an alley off 19th St NW between M and N streets, and has short lunchtime opening hours (11.45am to 2.15pm) Monday to Friday only, it's not going to work for many tourists. But if you are around Dupont Circle at that time, then it's worth hunting down.

While we're on the subject of good, cheap DC fast food, there's also Alberto's pizza, with an outlet on 18th St in Adams Morgan and one on P Street in Dupont Circle. It's open until 5am on the weekend and you get a huge slice for $4.