Being "distinct" is at once the greatest strength and the greatest vulnerability for Africa's immigrant entrepreneurs
Generations of Africans have debated the merits of foreign-controlled enterprise: do these businesses and the people who run them strengthen or undermine local economic opportunity? Do they benefit or exploit local workers and consumers?
Such debates often overlook that a large portion of these foreign-owned firms are small or medium enterprises, and that their owners are not European, North American or even Chinese.
The commercial success of certain "middleman minority" groups, such as Indians in east Africa or Lebanese in west Africa, is widely known. Far more foreign business owners on the continent, however, originate in other African countries.
Their ranks include Somalis in South Africa, Nigerian Hausas in Ghana and Mauritanian Arabs in Senegal. They run a broad spectrum of businesses, from factories to dry goods stores to tailor shops.
These African immigrant entrepreneurs' vital role in host country economies has too often been misunderstood by observers and maligned by overzealous nationalists and cynical politicians.
Even after having established themselves, started businesses and learned local languages, immigrants often remain socially and culturally distinct from the host population. Their linguistic or religious traditions may set them apart.
These groups frequently maintain and cultivate enduring ties with their country of origin. Many send their children born in the host country to be raised by relatives back home, the better to instil in them the culture, language and values of their community of origin.
When these offspring come of age, they rejoin their parents abroad and eventually take over their businesses and properties, perpetuating their families' presence in the host country.
So although integrated into the host society in fundamental ways, such immigrants do not fully assimilate into it, even after generations.
They are like a highly visible thread woven into, yet discrete from, the social fabric of the host country. The distinct status of these populations - "strangers" as some call them - is at once their greatest strength and their greatest vulnerability. (The use of the term "strangers" to refer to immigrant traders in west Africa has a long history in scholarship on the subject.)
Immigrants and their descendants can draw important economic benefits from their foreigner status. At home, the imperatives of successful entrepreneurship, such as making a profit and accumulating capital, frequently conflict with the imperatives of dutiful kinship, such as supporting the needy, offering credit, or providing discounts.
Abroad, as nominal outsiders, immigrants are not bound by the same webs of reciprocal obligation: they can afford to scale back their social obligations and invest more in their enterprises than if they had never left home.
Although they still rely heavily on their own kin and co-ethnics abroad, immigrants stand apart from their clientele. Hence they enjoy more freedom to run their businesses as they see fit.
The tightly knit, kin-based nature of foreigner communities also fosters a degree of internal cohesion that the wider host society usually lacks. These migrants' status as "strangers in a strange land" heightens their sense of shared identity and mutual responsibility.
This cohesion gives rise to "enforceable trust", a mechanism for punishing malfeasance and rewarding good behaviour. Immigrants can ill afford alienation from their own community, and thus must abide by the group's internal norms.
Enforceable trust fills the void left by a dysfunctional formal legal system in settings where state institutions are weak, courts corrupt and contract enforcement uncertain - as is often the case in some African countries.
Immigrants also stand to benefit from their transnational connections. This writer studied traders from 2005 to 2006 in Brazzaville, capital of the Republic of Congo.
They belonged to networks linking them not only with their villages of origin in the western Sahel - especially Mali, Guinea and Senegal - but with kin and co-ethnics based in Angola, Côte d'Ivoire, Nigeria, South Africa and as far afield as Thailand, the United Arab Emirates and China.
Many had previously lived in some of these other cities and countries in their migrant network before coming to Congo. Travel between these nodes was a regular feature of doing business for the more successful entrepreneurs.
Even family-owned businesses can manage risk by diversifying operations across multiple countries. A Malian entrepreneur I interviewed operates a metal sheeting plant in the Republic of Congo, has one relative in charge of his Congolese sawmill, another running his plastics factory in Mali and a third managing his export office in south-eastern China.
Such transnational networks lower business costs by making it easier to share information and technologies across borders.
Small-scale, kin-based firms thrive in impoverished African economies where profit margins are narrow, credit is tight and conditions are risky.
Their flexible structure and ability to self-regulate allow them to enter markets which larger, better-capitalised multinational firms find either too marginal or too hazardous to enter.
Yet "stranger" status is a double-edged sword. As members of a distinct and highly visible minority, immigrants are susceptible to abuse by host country citizens and governments. Hosts typically harbour negative stereotypes about foreigners, insulting them as "illegal aliens" and parasites who take advantage of local consumers and expatriate their profits.
Such perceptions can fuel xenophobic violence, as happened in May 2008, when mobs attacked immigrants in South African townships, leaving at least 62 dead and thousands homeless.
In 2013, two Somali shopkeepers were hacked to death in Limpopo province, and a third stoned to death in Port Elizabeth. A video of the stoning was posted to the internet, a graphic reminder of the perils that accompany foreigners.
More often, hosts' negative perceptions amplify everyday social tensions and discrimination. Congolese public officials levy all manner of bogus fees on foreign African shopkeepers in Brazzaville, knowing that these immigrants are resigned to such treatment and unlikely to protest.
Ordinary Congolese perceived west African merchants as "free riders" who profited from local communities without giving back. Merchants canvassed during my fieldwork, however, felt they paid far more than formal taxation and other legal payments, thanks to routine petty extortion.
At times, tensions have led to the mass expulsion of foreign Africans. Dozens of such evictions were carried out from the 1950s through the 1990s in countries including Angola, Côte d'Ivoire, Gabon, Uganda and Zambia. Most of these operations entailed a few thousand deportations.
The largest - in Nigeria in 1983 - uprooted 2m people, mostly from Ghana and other neighbouring countries, according to a 2002 paper by Marc-Antoine Pérouse de Montclos of the Institute of Policy Studies in Paris.
Nigerians still use this operation's unofficial moniker, "Ghana must go", as a nickname for the type of cheap plastic-fibre bags used by deportees to haul away their belongings.
Expulsion orders tend to be politically popular in the short term, as immigrants make convenient scapegoats for high unemployment and rising prices.
Yet expulsions never solve host countries' economic problems. The social factors underlying the for-eigners' economic success remain unchanged. Nationalised businesses eventually fail. Deportees slowly resume their activities and the whole affair is gradually forgotten.
Perhaps African governments have learned from their mistakes, as large-scale deportations have become less frequent over the past two decades.
Extensive expulsion operations have continued, however, in a few countries. Since 2009, Angola has deported tens of thousands of Congolese and west Africans, according to a 2012 report from the UN Office for the Coordination of Humanitarian Affairs.
South Africa deported more than 2.5m Zimbabweans between 1988 and 2010, according to Department of Home Affairs figures, quoted in "Contemporary Migration to South Africa: a Regional Development Issue", by Aurelia Segatti and Loren Landau.
Despite this sometimes sordid history, the relationship between African immigrants and their hosts is often mutually beneficial. By converting their outsider status into entrepreneurial success, foreigners provide goods and services for the host country's consumers, and formal and informal revenue for its public officials.
They frequently perform labour their hosts are unwilling to do. In Abidjan in Côte d'Ivoire, for example, locals view driving taxis, pushing hand trucks or any form of manual labour as degrading, suitable only for outsiders, as described in anthropologist Sasha Newell's 2012 book, "The Modernity Bluff: Crime, Consumption, and Citizenship in Côte d'Ivoire".
Immigrants, coversely, work in jobs they would have been unwilling to do at home: many Malian immigrants in Cameroon, for example, manufacture metal cooking pots for local consumption - even though taboos in their villages of origin bar them from working with metal.
The ability of "strangers" to operate in high-risk environments has helped reinvigorate stagnant, conflict-ravaged economies, such as in the Republic of Congo or Mozambique, where traders from several west African countries have operated.
Governments can strengthen the symbiotic nature of host-immigrant relations by earning foreigners' confidence. To do this, they must fortify the rule of law: wise entrepreneurs will not invest where they fear losing their property to greedy officials or mob violence, or where their official permits do not prevent extortion against them.
As long as migrants feel discriminated against and unable to enjoy equal protection under the law, they and their hosts will view each other with suspicion and the full potential benefits of their interaction will not be realised.
This article has been changed from the print version; 'strangers' is used instead of 'étrangers', and a date has been corrected.