The owners of 120 Watling Street, Strangford Property Consultancy Ltd, applied at the beginning of this year for a change of use from retail store to a coffee shop.
The previous tenants, Towcester Home, closed the store following strong competition from national retailers and out of town DIY stores.
Yesterday evening Towcester mayor councillor Chris Lofts told fellow councillors he had attended the South Northants Council planning committee to object on their behalf.
Mr Lofts said the application had been recommended for approval by council officers following a commitment by the owners that if permission was granted then it would only be sold to one of five national brands.
They were Costa Coffee, Caffè Nero, Starbucks, Pret A Manger or Coffee Republic.
Other conditions on the approval include a ban on the cooking of unprepared food and agreement on opening hours.
Councillor Martin Johns feared the town centre would lose its individual character and added: "It's the same thing you see up and down the country."
Councillor Jacqueline Hart said the property had been marketed for at least a year without success and said that if the permission had not been granted Towcester would have another empty shop.
Councillor Charles Stanger agreed adding: "We do not want another Brackley."
Sally Stroman of Wilbraham Associates, who are acting as agents for the owners, said the property had been actively marketed over 12 months with no committed interest from retailers.
Mrs Stroman added: "We consider that the coffee shop proposal will complement the district council's aspirations to widen tourist based activities within the town and as such will contribute positively to the attractiveness, vitality and viability of Watling Street."