It's my evil side; I love resurrect old topics...
In fact, QC road signs were bilingual until the first Parti Quebecois separatist government, elected in 1976, decided to turn them all french only.
No, that would be the
Loi sur la langue officielle (Bill 22), adopted in 1974 by a National assembly comprising a vast majority (93%) of unionist (Liberal) MPs. That bill established French as the official language for governmental services as well as legislation and justice ― among others. The metric conversion sign replacement program featured monolingual signs.
Some exceptions exist in some areas, especially around Montreal. In some english-speaking parts of the city, some municipal signs are still bilingual.
No. These exceptions are, in absolute figures, primarily outside the Greater Montréal. The French Language Charter's section 29.1 grandfathered in the possibility for non-provincial public institutions (municipalities, local development centres, housing bureaus, etc.) serving a majority of English-speakers to offer prominently English services. A majority of these institutions (including west island communities) do not serve a majority of English speakers anymore; the the bilingual acknowledgement stays until the institution itself asks for removal.
Note that even though the 2001 mass town mergers disbanded municipal institutions, the boroughs they formed have kept bilingual designation.
I think some people, at the MTQ, have a direct dislike for english language. But this is another story!
MTQ workers obey the provincial statutes and regulations, the
Regulation respecting the signs and posters of the civil administration prescribing French road signage among others.
Speaking of indian reserves, the Abenaki reserve of Odanak have a trilingual stop sign. The shot dates from Sept. 2014, I don't know if the sign was replaced since.
Odanak still has and maintains trilingual Français/English/W8banaki8dwaw8gan signs.
In Quebec's far northern Kativik region, the stop signs and street signs in the "county seat" Kuujjuaq are bilingual Inuktitut-English, not a trace of French.
Regarding the special northern regime, Kuujjuaq would be more of a "capital" for the Kativik regional government ― the closest thing to a protectorate in Québec. The territory under KRG administration is subtracted from the application of numerous statutes and regulations or parts of them in various domains (health, education, environment, ...), although
jus soli remains québécois. This also applies to institutional/official language.
Regarding commercial signage, one of the most famous, or infamous depending on your point of view, examples is surely a well-known fast-food chain. I believe I read somewhere that the language police decided the full name is merely descriptive of what they sell, so it had to be in French.
The "language police" you are referring to is KFC itself in this case. The name PFK was current well before the Charter came in effect in 1979. KFC replaced
Chez Scott - La villa du poulet joints in some places, a chain somewhat related to KFC that also adapted to the cultural context, being known as Scott's Chicken Villa in its hometown of Toronto. KFC and Staples were may be advised to change their name, but never would they have been forced to do so. Other American or Canadian chains that opened joints or shops in Québec made the choice of keeping their original namesake (Burger King, Dairy Queen, Home Depot, The Brick, Jack Astor's Bar & Grill, Best Buy, Canadian Tire, Future Shop, Costco Wholesale, ...).
The Charter of the French Language does not force any corporation to change its name, but rather suggests to add a French element to signs (
Les cafés Second Cup, Home Depot
l'entrepôt de la rénovation au Québec, etc.). If you do not pay attention, you would not even notice. Former Liberal (unionist) Culture and French language minister proposed last year that this become an obligation ― which it did not.