The French-born entrepreneur was even handed the 2009 Emerging New Business Accolade by Mr Cowen at a glittering ceremony at the Mansion House.
However before Christmas his Bastille Bistro restaurant in Letterkenny closed down just eight months after opening. A previous restaurant on the site – Catch Up – quickly won a reputation for bad food and poor service and also closed.
And his Fasre estate agency business and Etic Solutions businesses, mainly based in Ballybofey, appear to have ceased trading.
Donegaldaily.com has made numerous attempts to interview Mr Dietrich to ask him about how he felt hitting the bottom after such highs just 18 months ago, but we have been unable to reach him.
After being handed his award by the Taoiseach, the Frenchman said: “This award recognises our innovative approach to business and the continuing need for creativity in this uncertain market.
“We think outside the box at ETIC to provide services in a very different and fresh way, primarily to the tourism and hospitality industry, through the launch of a new international hotel brand to Ireland, as well as a contemporary restaurant chain.
“Etic Solution’s portfolio of businesses also include an estate agency that implements an innovative marketing approach, the only specialised chef recruitment agency in Ireland, a French Language school, event management and PR agency.”
The businessman had already bagged an award and a grant from the County Enterprise Board.
During his time in Donegal, Mr De Dietrich made many friends, particularly in GAA and rugby circles.
He once sponsored a ‘Beat the Banker’ charity night held at the Mount Errigal Hotel to raise money for a local school – and also put money into sponsoring Letterkenny Chamber of Commerce.
There were reports recently that he may have moved to Belfast where he also owned a French restaurant also called Bastille on the trendy Lisburn Road in the south of the city.
However when donegaldaily.com spoke to that restaurant last night we were told: “Francois has nothing to do with this restaurant anymore.
“It is under new management. Francois sold the restaurant four weeks ago.”
When we called to his home in Ballybofey, there was no answer to his home – and an answering machine at his home number is so jammed with messages, it cannot take anymore.
Last night one local businessman who knows Mr De Dietrich well told us: “It is absolutely amazing how many people Francois got to know here in Donegal and in other Border counties.
“Many of them have been asking about him and are wondering if he has moved back to France or another European country.
“He would be known to most of the movers and shakers in the county and would have had business dealings with many of them.
“But his whereabouts at the moment is something of a mystery.”
Do you know where Mr de Dietrich is? firstname.lastname@example.org