According to Vasileva (2009) in the beginning of 2008, 30.8 million non-nationals were living in the EU-27 Member States, constituting 6.2% of the total European population. Nearly one third (11.3 millions) were from one of the EU-27 Members states, while nearly 20% were from a non-European country: 15.2% from Africa followed by Asia (12%) and America (10.3%). In terms of demographic characteristics, the ESPON project 1.1.4 (2005*) characterised the majority (56%) of the immigrants as being between 25 and 55 years old. On average, immigrants tend to be younger than the host population (Kröhnert et al., 2008*) and the oldest immigrant population was mainly from Southern Europe, as well as migrants from north-western, living in another EU country (presumably retirement migrants) (ESPON, 2005*, project 1.1.4). In terms of gender, in 2000, more than 52% of immigrants were women (Gallotti, 2009). Nonetheless this representation is not linear since, as pointed out by the ESPON project 1.1.4 (2005), women were over-represented among immigrants from the Balkans, Central and Eastern Europe and from Latin America, as well as immigrants from north-western Europe. On the other hand, immigrants from Turkey, North Africa, Middle East and sub-Saharan Africa were mainly men.
Most of the international immigrants settle down in urban areas due to the economic, cultural and social opportunities that large cities can offer (Malgesini, 2006*). Along with these opportunities, the available market for non-skilled jobs (Fonseca, 2001; Malheiros, 2002*; Malheiros and Vala, 2004*), social networks (use of human capital inherent in the ethnic networks, relatives and friends in the host country, information) (Arapoglou, 2006*; Hårsman, 2006; Malgesini, 2006*; Malheiros, 2002*; Malheiros and Vala, 2004*), family reunion (Deurloo and Musterd, 1998*), labour recruitment policy and historical and cultural links (colonial past and share of same language) (Deurloo and Musterd, 1998; Malheiros, 2002*; Malheiros and Vala, 2004*) result in “pull factors” to immigrants.
The settlement of immigrants and the demographic growth of their descendants has a social impact on cities (Malheiros and Vala, 2004*) contributing, in some cases, to a high degree of urbanisation (Malgesini, 2006) Spatial segregation in some cases is a consequence of the presence of immigrants in cities (Gaspar, 2001). Ethnic segregation in Europe is related to the recent waves of international immigration characterised by labour immigrants, immigrants from the former European colonies and refugees, (Fortuijn et al., 1998*). In the American literature, under the influence of the Chicago School, it is possible to find references to the idea of “ghetto”, representing an idea of high levels of urban segregation and poverty (Fortuijn et al., 1998*). In the European context “few ghettos can be found”, mainly due to the recent experience of segregation (Fortuijn et al., 1998, p. 367). Nevertheless, in a different scale from the American context, “segregation also shapes cities” (Kaplan and Woodhouse, 2004, p. 580). Segregation is seen has a failure of assimilation of the ethnic minorities and most of the countries aim to reduce ethnic residential division. (Malheiros, 2002) has also identified two different scenarios in Europe regarding the settlement of immigrants and segregation patterns: the southern European cities are characterised by low levels of ethnic and social segregation, while the Northern European cities present higher levels of segregation. He considers the differences in immigration (different periods of migration, the multiplicity of immigrants and the high percentage of non-legal immigrants involved in informal activities in the southern European Countries) and the divergence of urban and house policies (“late industrialisation and suburbanisation”, lack of public housing in the southern European Countries) (Malheiros and Vala, 2004*, p. 1067) as key elements for these differences. As an example of this scenario, in Greece, Albanian immigrants experience a low index of segregation in Athens, mainly through their capacity to live among the Greek population and in different areas of the city (Arapoglou, 2006). However, other immigrants from central and eastern Europe, and also from Asian and African countries have their own communities and tend to live closer together and somewhat more segregated, and examples can be found in the literature. The civil unrest which occurred in the Parisian suburbs (banlieus) in 2005 could be seen as one example of the consequences of a certain degree of ethnic segregation. In his studies of these “sensitive neighbourhoods” in Paris (Shon, 2010, p. 1603) concluded that the more disadvantaged the neighbourhood is, the harder it is for its residents to move into a less deprived area. As an example, he pointed out the fact that Africans faced more challenges to move out, being instead more prone to move into the least-advantaged neighbourhoods. In Italy, Mingione (2009) refers to examples of social tension between the resident population and the foreigner communities (Chinese and Romanian) in Milan, as an example of ethno-spatial conflicts and apprehension among ethnic communities. (Arapoglou and Sayas, 2009) identified a certain degree of spatial segregation based on gender and employment, not only among female immigrants but also the resident population. According to these authors female domestic and unskilled service migrant workers tend to be located in city centre and suburban areas, while intra-movements of local residents are also present.